Synthesis and pharmacological evaluation of 3‐(4‐chloro phenyl)‐2‐substituted‐3H‐quinazolin‐4‐ones as analgesic and anti‐inflammatory agents

A new series of 3‐(4‐chloro phenyl)‐2‐substituted‐3H‐quinazolin‐4‐ones were synthesized by reacting the amino group of 2‐hydrazino‐3‐(4‐chloro phenyl)‐3H‐quinazolin‐4‐one with different aldehydes and ketones. The compounds were investigated for their analgesic activity in albino mice, and for their anti‐inflammatory and ulcerogenic activities in Wistar rats. All test compounds exhibited analgesic and anti‐inflammatory activities. Compound VA2 (2‐(1‐ethylpropylidene‐hydrazino)‐3‐(4‐chloro phenyl)‐3H‐quinazolin‐4‐one) showed moderately more potent analgesic activity and compound VA3 (2‐(1‐methylbutylidene‐hydrazino)‐3‐(4‐chlorophenyl)‐3H‐quinazolin‐4‐one) showed moderately more potent anti‐inflammatory activity when compared with the reference standard, diclofenac sodium. The test compounds showed only mild ulcerogenic side effects when compared with aspirin. Drug Dev Res 69: 226–233, 2008 ©2008 Wiley‐Liss, Inc.     

Synthesis and Evaluation of Novel 2‐Substituted‐quinazolin‐4(3H)‐ones as Potent Analgesic and Anti‐inflammatory Agents

A novel series of 2‐substituted‐quinazolin‐4(3H)‐ones were synthesized by reacting 3,5‐disubstituted‐anthranilic acid with acetic anhydride/benzoyl chloride, which were further reacted with different primary amines to obtain 2,6,8‐substituted‐quinazolin‐4(3H)‐ones 6a–f , 7 , 8 . All the synthesized compounds were characterized and screened for analgesic and anti‐inflammatory activities. Compounds 6,8‐dibromo‐2‐phenyl‐3‐(4′‐carboxyl phenyl)quinazolin‐4(3H)‐one 7 and 6,8‐dibromo‐2‐phenyl‐3‐(2′‐phenylethanoic acid)quinazolin‐4(3H)‐one 8 displayed good analgesic and anti‐inflammatory activity in comparison to the reference standards acetyl salicylic acid and indomethacin, respectively.     

Synthesis,analgesic, anti‐inflammatory and ulcerogenic index activities of novel 2‐methylthio‐3‐substituted‐5,6‐dimethyl thieno [2,3‐d] pyrimidin‐4(3H)‐ones

A variety of novel 2‐methylthio‐3‐substituted amino‐5,6‐dimethyl thieno [2,3‐d] pyrimidin‐4(3H)‐ones were synthesized by reacting 3‐amino‐2‐methylthio‐5,6‐dimethyl thieno [2,3‐d] pyrimidin‐4(3H)‐one with different aldehydes and ketones. The starting material 3‐amino‐2‐methylthio‐5,6‐dimethyl thieno [2,3‐d] pyrimidin‐4(3H)‐one was synthesized from 2‐amino‐3‐carbethoxy‐4,5‐dimethyl thiophene. The compounds were investigated for their analgesic activity in albino mice, and for their anti‐inflammatory and ulcerogenic index activities in Wistar rats. The compound 2‐(1‐ethylpropylideneamino)‐2‐methylthio‐5,6‐dimethyl thieno [2,3‐d] pyrimidin‐4(3H)‐one (AS2) showed the most potent analgesic activity of the series. It also showed more potent anti‐inflammatory activity when compared to the reference standard, diclofenac sodium. The test compounds showed only mild ulcerogenic potential when compared to aspirin. Drug Dev Res 68:134–142, 2007. © 2007 Wiley‐Liss, Inc.     

Novel 3,6‐Disubstituted 7H‐1,2,4‐Triazolo[3,4‐b][1,3,4]thiadiazines: Synthesis,Characterization, and Evaluation of Analgesic / Anti‐inflammatory,Antioxidant Activities

In this study, the synthesis of a new series of 3,6‐disubstituted‐7H‐1,2,4‐triazolo[3,4‐b][1,3,4]thiadiazine 1a – 4c compounds derived from 4‐amino‐3‐substituted‐1,2,4‐triazole‐5‐thiones 1 – 4 is described. All of the synthesized compounds were screened for their possible analgesic / anti‐inflammatory, antioxidant activities and gastric toxicity. The compound 2c was found to have both significant analgesic and consistent anti‐inflammatory activity without inducing any gastric lesions along with minimal lipid peroxidation. A deep insight into the structures of the active compounds revealed that the compounds carrying an electron withdrawing group (a chloride or fluoride) on the phenyl ring at 6‐position of the condensed heterocyclic derivatives exhibited noticeable higher activity.     

Synthesis and pharmacological investigation of novel 3-(benzyl)-2-substituted amino-3<Emphasis Type="Italic">H</Emphasis>-quinazolin-4-ones as analgesic and anti-inflammatory agents

A variety of novel 3-(benzyl)-2-substituted amino-quinazolin-4(3H)-ones were synthesized by reacting the amino group of 3-benzyl-2-hydrazino quinazolin-4(3H)-one with a variety of aldehydes and ketones. The starting material, 3-benzyl-2-hydrazino quinazolin-4(3H)-one, was synthesized from benzyl amine. The title compounds were investigated for analgesic, anti-inflammatory, and ulcerogenic index activities. The compound 3-benzyl-2-[N’-(1-ethyl-propylidene)-hydrazino]-3H-quinazolin-4-one (AS2) emerged as the most active compound of the series and is moderately more potent in its analgesic and anti-inflammatory activities when compared to the reference standard diclofenac sodium. Interestingly the test compounds showed only mild ulcerogenic potential when compared to aspirin.     

Synthesis and analgesic, anti-inflammatory activities of 3-(3-methoxyphenyl)-2-substituted amino-quinazolin-4(3H)-ones

A variety of novel 3-(3-methoxyphenyl)-2-substituted amino-quinazolin-4(3H)-ones were synthesized by reacting the amino group of 2-hydrazino-3-(3-methoxyphenyl)-quinazolin-4(3H)-one with a variety of aldehydes and ketones. The starting material 2-hydrazino-3-(3-methoxyphenyl)-quinazolin-4(3H)-one was synthesized from 3-methoxy aniline. The title compounds were investigated for analgesic, anti-inflammatory, and ulcerogenic behavior. Among these the compound 2-(1-methyl butylidene-hydrazino)-3-(3-methoxyphenyl)-3H-quinazolin-4-one (AS3) emerged as the most active compound for the analgesic activity, while the compound 2-(1-ethyl propylidene-hydrazino)-3-(3-methyoxyphenyl)-3H-quinazolin-4-one (AS2) showed most potent anti-inflammatory activity of the series and these compounds are moderately more potent when compared to the reference standard diclofenac sodium. Interestingly the test compounds showed only mild ulcerogenic potential when compared to acetylsalicylic acid.     

Synthesis of New 2,3‐Dihydroquinazolin‐4(1H)‐one Derivatives for Analgesic and Anti‐inflammatory Evaluation

Starting from isatoic anhydrides, several new 2,3‐dihydroquinazolin‐4(1H)‐one derivatives bearing chalcone or pyrazole or thiazole moieties at the third position were synthesized. The analgesic and anti‐inflammatory activities for most compounds were studied at a dose level of 50 mg/kg via the acetic‐acid‐induced writhing‐response method and carrageenan‐induced edema method, respectively. The study showed that the chalcones bearing a 4‐chlorophenyl group 4c or 4‐nitrophenyl group 4b were the most active ones as analgesics. Both chalcone 4c and N‐phenyl pyrazole bearing 4‐methoxy phenyl group 5b showed a higher anti‐inflammatory activity than celecoxib but still lower than that of diclofenac sodium. Moreover, the chalcone 4c has nearly the same ulcerogenic index as the selective cyclooxygenase‐2 inhibitor celecoxib.     

Synthesis,p38α MAP kinase inhibition,anti‐inflammatory activity,and molecular docking studies of 1,2,4‐triazole‐based benzothiazole‐2‐amines

Recent studies have demonstrated that inhibition of p38α MAP kinase could effectively inhibit pro‐inflammatory cytokines including TNF‐α and interleukins. Thus, inhibition of this enzyme can prove greatly beneficial in the therapy of chronic inflammatory diseases. A new series of N‐[3‐(substituted‐4H‐1,2,4‐triazol‐4‐yl)]‐benzo[d]thiazol‐2‐amines ( 4a–n ) were synthesized and subjected to in vitro evaluation for anti‐inflammatory activity (BSA anti‐denaturation assay) and p38α MAPK inhibition. Among the compounds selected for in vivo screening of anti‐inflammatory activity ( 4b , 4c , 4f , 4g , 4j , 4m , and 4n ), compound 4f was found to be the most active with an in vivo anti‐inflammatory efficacy of 85.31% when compared to diclofenac sodium (83.68%). It was also found to have a low ulcerogenic risk and a protective effect on lipid peroxidation. The p38α MAP kinase inhibition of this compound (IC₅₀ = 0.036 ± 0.12 μM) was also found to be superior to the standard SB203580 (IC₅₀ = 0.043 ± 0.27 μM). Furthermore, the in silico binding mode of the compound on docking against p38α MAP kinase exemplified stronger interactions than those of SB203580.

     

New pyrazole derivative 5‐[1‐(4‐fluorophenyl)‐1H‐pyrazol‐4‐yl]‐2H‐tetrazole: synthesis and assessment of some biological activities

The molecular modification and synthesis of compounds is vital to discovering drugs with desirable pharmacological and toxicity profiles. In response to pyrazole compounds' antipyretic, analgesic, and anti‐inflammatory effects, this study sought to evaluate the analgesic, anti‐inflammatory, and vasorelaxant effects, as well as the mechanisms of action, of a new pyrazole derivative, 5‐[1‐(4‐fluorophenyl)‐1H‐pyrazol‐4‐yl]‐2H‐tetrazole. During the acetic acid‐induced abdominal writhing test, treatments with 5‐[1‐(4‐fluorophenyl)‐1H‐pyrazol‐4‐yl]‐2H‐tetrazole reduced abdominal writhing, while during the formalin test, 5‐[1‐(4‐fluorophenyl)‐1H‐pyrazol‐4‐yl]‐2H‐tetrazole reduced licking times in response to both neurogenic pain and inflammatory pain, all without demonstrating any antinociceptive effects, as revealed during the tail flick test. 5‐[1‐(4‐fluorophenyl)‐1H‐pyrazol‐4‐yl]‐2H‐tetrazole also reduced carrageenan‐induced paw edema and cell migration during the carrageenan‐induced pleurisy test. As demonstrated by the model of the isolated organ, 5‐[1‐(4‐fluorophenyl)‐1H‐pyrazol‐4‐yl]‐2H‐tetrazole exhibits a vasorelaxant effect attenuated by Nω‐nitro‐l ‐arginine methyl ester, 1H‐[1,2,4]oxadiazolo[4,3‐alpha]quinoxalin‐1‐one, tetraethylammonium or glibenclamide. 5‐[1‐(4‐fluorophenyl)‐1H‐pyrazol‐4‐yl]‐2H‐tetrazole also blocked CaCl₂‐induced contraction in a dose‐dependent manner. Suggesting a safe toxicity profile, 5‐[1‐(4‐fluorophenyl)‐1H‐pyrazol‐4‐yl]‐2H‐tetrazole reduced the viability of 3T3 cells at higher concentrations and was orally tolerated, despite signs of toxicity in doses of 2000 mg/kg. Lastly, the compounds' analgesic activity might be attributed to the involvement of the NO/cGMP pathway and K⁺ channels observed in the vasorelaxant effect.     

Synthesis of Novel Substituted Thiourea and Benzimidazole Derivatives Containing a Pyrazolone Ring as Anti‐Inflammatory Agents

Two series of new 1‐(alkyl/aryl)‐3‐{2‐[(5‐oxo‐4,5‐dihydro‐1H‐pyrazol‐3‐yl)amino]phenyl}thioureas 2a – h and 5‐[2‐(substituted amino)‐1H‐benzimidazol‐1‐yl]‐4H‐pyrazol‐3‐ols 3a – i were designed and synthesized as anti‐inflammatory agents. The cyclooxygenase inhibitory activity of the newly synthesized compounds was investigated. All the compounds showed non‐selective inhibition of COX‐1 and COX‐2 enzymes which was consistent with their docking results. Compounds 2c , 2f , 2g , 3b , and 3g that showed the highest COX‐2 inhibitory activity were selected for further in vivo testing as anti‐inflammatory agents using diclofenac as a reference drug. Two of the test compounds ( 2c and 3b ) showed potent anti‐inflammatory activity comparable to that of diclofenac with lower ulcerogenic effect relative to indomethacin. SAR study of the two series as cyclooxygenase inhibitors and anti‐inflammatory agents was also provided.     

Pharmacological and metabolic characterisation of the potent σ1 receptor ligand 1′‐benzyl‐3‐methoxy‐3H‐spiro[[2]benzofuran‐1,4′‐piperidine]

Objectives The pharmacology and metabolism of the potent σ1 receptor ligand 1′‐benzyl‐3‐methoxy‐3H‐spiro[[2]benzofuran‐1,4′‐piperidine] were evaluated. Methods The compound was tested against a wide range of receptors, ion channels and neurotransmitter transporters in radioligand binding assays. Analgesic activity was evaluated using the capsaicin pain model. Metabolism by rat and human liver microsomes was investigated, and the metabolites were identified by a variety of analytical techniques. Key findings 1′‐Benzyl‐3‐methoxy‐3H‐spiro[[2]benzofuran‐1,4′‐piperidine] (compound 1 ) is a potent σ1 receptor ligand (K_i 1.14 nM) with extraordinarily high σ1/σ2 selectivity (>1100). It was selective for the σ1 receptor over more than 60 other receptors, ion channels and neurotransmitter transporters, and did not interact with the human ether‐a‐go‐go‐related gene (hERG) cardiac potassium channel. Compound 1 displayed analgesic activity against neuropathic pain in the capsaicin pain model (53% analgesia at 16 mg/kg), indicating that it is a σ1 receptor antagonist. It was rapidly metabolised by rat liver microsomes. Seven metabolites were unequivocally identified; an N‐debenzylated metabolite and a hydroxylated metabolite were the major products. Pooled human liver microsomes formed the same metabolites. Studies with seven recombinant cytochrome P450 isoenzymes revealed that CYP3A4 produced all the metabolites identified. The isoenzyme CYP2D6 was inhibited by 1 (IC50 88 nM) but did not produce any metabolites. Conclusions 1′‐Benzyl‐3‐methoxy‐3H‐spiro[[2]benzofuran‐1,4′‐piperidine] is a potent and selective σ1 receptor antagonist, which is rapidly metabolised. Metabolically more stable σ1 ligands could be achieved by stabilising the N‐benzyl substructure.     

Synthesis of novel 3-butyl-2-substituted amino-3H-quinazolin-4-ones as analgesic and anti-inflammatory agents

A variety of novel 3-butyl-2-substituted amino-3H-quinazolin-4-ones were synthesized by reacting the amino group of 3-butyl-2-hydrazino-3H-quinazolin-4-one with various aldehydes and ketones. The title compounds were investigated for analgesic, anti-inflammatory and ulcerogenic index activities. The compound 3-butyl-2-(1-methylbutylidene-hydrazino)-3H-quinazolin-4-one (AS3) emerged as the most active analgesic agent. Compound 3-butyl-2-(1-ethylpropylidene-hydrazino)-3H-quinazolin-4-one (AS2) emerged as the most active anti-inflammatory agent and is moderately more potent when compared to the reference standard diclofenac sodium. Interestingly, the test compounds showed only mild ulcerogenic potential when compared to aspirin.     

1‐[(2,3‐Dihydro‐1‐benzofuran‐2‐yl) methyl]piperazines as novel anti‐inflammatory compounds: Synthesis and evaluation on H3R/H4R

The histamine receptors (HRs) are members of G‐protein‐coupled receptor superfamily and traditional targets of huge therapeutic interests. Recently, H₃R and H₄R have been explored as targets for drug discovery, including in the search for dual‐acting H₃R/H₄R ligands. The H₄R, the most recent histamine receptor, is a promising target for novel anti‐inflammatory agents in several conditions such as asthma and other chronic inflammatory diseases. Due to similarity with previously reported ligands of HRs, a set of 1‐[(2,3‐dihydro‐1‐benzofuran‐2‐yl)methyl]piperazines were synthesized and evaluated in competitive binding assays as H₃R/H₄R ligands herein. The results showed the compounds presented affinity (K_i) for H₃R/H₄R in micromolar range, and they are more selective to H₃R. All the compounds showed no important cytotoxicity to mammalian cells. The phenyl‐substituted compound LINS01005 has shown the higher affinity of the set for H₄R, but no considerable selectivity toward this receptor over H₃R. LINS01005 showed interesting anti‐inflammatory activity in murine asthma model, reducing the eosinophil counts in bronchoalveolar lavage fluid, as well as the COX‐2 expression. The presented compounds are valuable prototypes for further improvements to achieve better anti‐inflammatory agents.     

Design and Synthesis of 2‐Phenoxynicotinic Acid Hydrazides as Anti‐inflammatory and Analgesic Agents

A series of 2‐phenoxynicotinic acid hydrazides were synthesized and evaluated for their analgesic and anti‐inflammatory activities. Several compounds having an unsubstituted phenyl/4‐pyridyl or C‐4 methoxy substituent on the terminal phenyl ring showed moderate to high analgesic or anti‐inflammatory activity in comparison to mefenamic acid as the reference drug. The compounds with highest anti‐inflammatory activity were subjected to in vitro COX‐1/COX‐2 inhibition assays and showed moderate to good COX‐1 and weak COX‐2 inhibition activities.     

Physicochemical and biological evaluation of a cinnamamide derivative R,S‐(2E)‐1‐(3‐hydroxypiperidin‐1‐yl)‐3‐phenylprop‐2‐en‐1‐one (KM‐608) for nervous system disorders

A cinnamamide scaffold has been successfully incorporated in several compounds possessing desirable pharmacological activities in central and peripheral nervous system such as anticonvulsant, antidepressant, neuroprotective, analgesic, anti‐inflammatory, muscle relaxant, and sedative/hypnotic properties. R,S‐(2E)‐1‐(3‐hydroxypiperidin‐1‐yl)‐3‐phenylprop‐2‐en‐1‐one (KM‐608), a cinnamamide derivative, was synthesized, its chemical structure was confirmed by means of spectroscopy and crystallography, and additionally, thermal analysis showed that it exists in one crystalline form. The compound was evaluated in vivo in rodents as anticonvulsant, antiepileptogenic, analgesic, and neuroprotective agent. The beneficial properties of the compound were found in animal models of seizures evoked electrically (maximal electroshock test, 6‐Hz) and chemically (subcutaneous pentylenetetrazole seizure test) as well as in three animal models of epileptogenesis: corneal‐kindled mice, hippocampal‐kindled rats, and lamotrigine‐resistant amygdala‐kindled rats. Quantitative pharmacological parameters calculated for the tested compound were comparable to those of currently used antiepileptic drugs. In vivo pharmacological profile of KM‐608 corresponds with the activity of valproic acid.     

Synthesis of Novel Oxazolo[4,5‐b]pyridine‐2‐one based 1,2,3‐triazoles as Glycogen Synthase Kinase‐3β Inhibitors with Anti‐inflammatory Potential

A novel series of oxazolo[4,5‐b]pyridine‐2‐one based 1,2,3‐triazoles has been synthesized by click chemistry approach and evaluated for in vitro GSK‐3β inhibitory activity. Compound 4g showed maximum inhibition with IC₅₀ value of 0.19 μ m . Keeping in view the effect of GSK‐3β inhibition on inflammation, compounds 4g , 4d , 4f , 4i , 4n and 4q exhibiting significant GSK‐3β inhibition were examined for in vivo anti‐inflammatory activity in rat paw edema model. The compounds 4g , 4d , 4f and 4i showed pronounced in vivo anti‐inflammatory activity (76.36, 74.54, 72.72 and 70.90%, respectively, after 5h post‐carrageenan administration) and were further found to inhibit the pro‐inflammatory mediators, viz. NO, TNF‐ α , IL‐1 β , and IL‐6 substantially in comparison with indomethacin, an anti‐inflammatory drug as well as SB216763, a GSK‐3 β inhibitor, reported to exert a similar effect. Histopathology studies confirmed the tolerance of gastric mucosa to these compounds.     

Synthesis,molecular docking,and pharmacological evaluation of N‐(2‐(3,5‐dimethoxyphenyl)benzoxazole‐5‐yl)benzamide derivatives as selective COX‐2 inhibitors and anti‐inflammatory agents

A series of N‐(2‐(3,5‐dimethoxyphenyl)benzoxazole‐5‐yl)benzamide derivatives ( 3am ) was synthesized and evaluated for their in vitro inhibitory activity against COX‐1 and COX‐2. The compounds with considerable in vitro activity (IC₅₀ < 1 μM) were evaluated in vivo for their anti‐inflammatory potential by the carrageenan‐induced rat paw edema method. Out of 13 newly synthesized compounds, 3a , 3b , 3d , 3g , 3j , and 3k were found to be the most potent COX‐2 inhibitors in the in vitro enzymatic assay, with IC₅₀ values in the range of 0.06–0.71 μM. The in vivo anti‐inflammatory activity of these six compounds ( 3a , 3b , 3d , 3g , 3j , and 3k ) was assessed by the carrageenan‐induced rat paw edema method. Compounds 3d (84.09%), 3g (79.54%), and 3a (70.45%) demonstrated significant anti‐inflammatory activity compared to the standard drug ibuprofen (65.90%) and were also found to be safer than ibuprofen, by ulcerogenic studies. A docking study was done using the crystal structure of human COX‐2, to understand the binding mechanism of these inhibitors to the active site of COX‐2.

     

A Novel Antifungal Agent with Broad Spectrum: 1‐(4‐Biphenylyl)‐3‐(1H‐imidazol‐1‐yl)‐1‐propanone

A series of (1‐substituted aryl)‐3‐(1H‐imidazol‐1‐yl)‐1‐propanones was synthesized through the N‐alkylation of imidazole with 3‐dimethylamino‐1‐(substituted aryl)‐1‐propanone hydrochlorides (ketonic Mannich bases). A second series of N¹‐substituted imidazoles was obtained by the reduction of the carbonyl function of the imidazole–ketones in the previous series by means of NaBH₄. All of the compounds were evaluated for antifungal activity against 16 strains of Candida, and 3‐(1H‐imidazol‐1‐yl)‐1‐(4‐biphenylyl)‐1‐propanone emerged as a broad‐spectrum antifungal agent. Several 3‐(1H‐imidazol‐1‐yl)‐1‐(2′‐(substituted benzyl)oxyphenyl)‐1‐propanones were also active towards Candida kefyr.     

Synthesis and Pharmacological Investigation of 2‐(4‐Dimethylaminophenyl)‐3,5‐disubstituted thiazolidin‐4‐ones as Anticonvulsants

A new series of 2‐(4‐dimethylaminophenyl)‐3‐substituted thiazolidin‐4‐one‐5‐yl‐acetyl acetamides/benzamides were synthesized by the nucleophilic substitution of 3‐substituted‐2‐(4‐dimethylaminophenyl)‐thiazolidin‐4‐one‐5‐yl‐acetylchloride with acetamide and benzamide. The starting material 3‐substituted‐2‐(4‐dimethylaminophenyl)‐thiazolidin‐4‐one‐5‐yl‐acetylchloride was synthesized from 3‐substituted‐2‐(4‐dimethylaminophenyl)‐thiazolidin‐4‐one‐5‐yl‐acetic acid, which in turn was prepared by one‐pot reaction of amino component, p‐dimethylamino benzaldehyde and mercapto succinic acid. The title compounds were investigated for their anticonvulsant activities; among the test compounds, compound 2‐(4‐dimethylaminophenyl)‐3‐phenylamino‐thiazolidine‐4‐one‐5‐yl‐acetylbenzamide ( 14 ) emerged as the most active compound of the series and as moderately more potent than the reference standard diazepam.     

Highly Active Potential Antituberculotics: 3‐(4‐Alkylphenyl)‐4‐thioxo‐2H‐1,3‐benzoxazine‐2(3H)‐ones and 3‐(4‐Alkylphenyl)‐2H‐1,3‐benzoxazine‐2,4(3H)‐dihiones Substituted in Ring‐B by Halogen

A series of 6‐chloro‐3‐(4‐alkylphenyl)‐4‐thioxo‐2H‐1,3‐benzoxazine‐2(3H)‐ones, 7‐chloro‐3‐(4‐alkylphenyl)‐4‐thioxo‐2H‐1,3‐benzoxazine‐2(3H)‐ones, 6‐bromo‐3‐(4‐alkylphenyl)‐4‐thioxo‐2H‐1,3‐benzoxazine‐2(3H)‐ones, 6,8‐dibromo‐3‐(4‐alkylphenyl)‐4‐thioxo‐2H‐1,3‐benzoxazine‐2(3H)‐ones, 6‐chloro‐3‐(4‐alkylphenyl)‐2H‐1,3‐benzoxazine‐2,4(3H)‐dithiones, 7‐chloro‐3‐(4‐alkylphenyl)‐2H‐1,3‐benzoxazine‐2,4(3H)‐dithiones, 6‐bromo‐3‐(4‐alkylphenyl)‐2H‐1,3‐benzoxazine‐2,4(3H)‐dithiones and 6,8‐dibromo‐3‐(4‐alkylphenyl)‐2H‐1,3‐benzoxazine‐2,4(3H)‐dithiones was synthesized. The compounds exhibited in‐vitro activity against Mycobacterium tuberculosis, M. kansasii (two strains), and M. avium. 6‐bromo‐3‐(4‐propylphenyl)‐4‐thioxo‐2H‐1,3‐benzoxazin‐2(3H)‐one and 6‐bromo‐3‐(4‐propylphenyl)‐2H‐1,3‐benzoxazin‐2,4(3H)‐dithione are the most active compounds against M. tuberculosis. The activity is similar to isoniazid (INH). The compounds under study have a broad spectrum of activity against potential pathogenic strains. The replacement of the oxo group by thioxo group of 3‐(4‐alkylphenyl)‐2H‐1,3‐benzoxazine‐2,4(3H)‐diones often led to an improvement in the antimycobacterial activity against M. tuberculosis.