Different action of milrinone analogs in guinea-pig atria

1. Three new milrinone analogs, esters of 2-substituted 5-cyano-1,6-dihydro-6-oxo-3-pyridine carboxylic acids [compounds I, II and III] displaced 3H-CHA (N6-cyclohexyl[3H]-adenosine) from its binding sites to Ri receptors in the rat brain. 2. When tested on the contractile activity of electrically driven left atrium from reserpine-treated guinea-pigs, I induced marked positive inotropic activity, whereas the most lipophilic compounds II and III, induced negative inotropic effects. 3. These results suggest that the positive inotropic agent may act by displacing endogenous adenosine from its Ri inhibitory receptors in the atria, whereas the negative inotropic agents may act as agonists at the same adenosine receptor.     

An analysis of the mechanism of the inotropic action of some milrinone analogues in guinea-pig isolated atria.

1. It has been reported previously that the milrinone analogues, ethyl 5-cyano-1,6-dihydro-2-methyl-6-oxo-3 pyridine carboxylate (I) and ethyl 5-cyano-1,6-dihydro-2-ethyl-6-oxo-3 pyridine carboxylate (II) exert a positive inotropic effect (EC50 = 15.6 +/- 0.2 microM and 40.3 +/- 0.1 microM) both on spontaneously beating and on electrically driven atria from reserpine-treated guinea-pigs. In the present study the mechanism of the inotropic action of these two agents was investigated. 2. In electrically driven left atrium from reserpine-treated guinea-pigs the EC50 values for inotropic activity for compounds (I) and (II) corresponded to that of milrinone (EC50 = 25 +/- 0.1 microM) but compound (I) induced a greater maximum effect. This corresponded to a percentage increase in developed tension over control of 63 +/- 0.3 whereas the maximum inotropic effect of milrinone was 48 +/- 0.3 and that of compound (II) was 47 +/- 0.2. 3. The inotropic activity of compounds (I) and (II) (10-100 microM) was resistant to propranolol (0.1 microM), thus excluding the involvement of beta-adrenoceptors. 4. Since the inotropism induced by compounds (I) and (II) was not reduced by carbachol (1 nM-0.5 microM), an action involving changes in adenosine 3':5'-cyclic monophosphate (cyclic AMP) can be excluded. 5. The inotropic action of compounds (I) and (II) was blocked selectively by 8-phenyltheophyline (10 microM) or adenosine deaminase (2 u ml-1). 6. Both (I) and (II) inhibited, in an apparently competitive manner, the negative inotropic effect induced by N6-(L-phenylisopropyl) adenosine (L-PIA), a stable adenosine agonist.(ABSTRACT TRUNCATED AT 250 WORDS)     

Regioselective chlorination of 6-(5-methyl-2-oxo-4-imidazolin-4-yl)-6-oxohexanoic acid ethyl ester: A new synthesis of biotin

Regioselective chlorination of a methyl group in 6-(5-methyl-2-oxo-4-imidazolin-4-yl)-6-oxohexanoic acid ethyl ester via reaction with sulfuryl chloride in methylene chloride has been performed for the first time. The synthesis of 5-(2-oxo-2,3-dihydro-1H-thieno[3,4-d]imidazol-4-yl)pentanoic acid methyl and ethyl esters (tetradehydrobiotin esters) — key compounds in biotin (vitamin H) synthesis — has been developed proceeding from 6-(2-oxo-5-chloromethyl-4-imidazolin-4-yl)-6-oxohexanoic acid ester. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 40, No. 12, pp. 25–29, December, 2007.     

Synthesis and rat lens aldose reductase inhibitory activity of some benzopyran-2-ones

A number of 4,7-disubstituted benzopyran-2-ones were synthesized and evaluated for crude rat lens aldose reductase inhibitory activity. Substituents on position 4 included CH3, CO2H, CH2CO2H, CH = CHCO2H, and CH2CH2CO2H. The aromatic substituents included OH, OCH3, OCOCH3, CH2CH3, and Cl. Also included in the study were 3-oxo-3H-naphtho[2,1-b]pyran-1-acetic, 2-oxo-2H-naphtho[1,2-b]pyran-4-acetic, and 1-naphthylacetic acids. The benzopyran and naphthopyran derivatives were prepared by the classical von Pechmann reaction. General structure-activity relationships reveal that optimal enzyme inhibitory activity is displayed by those compounds possessing the acetic acid moiety. For example, the most potent derivative, 3-oxo-3H-naphtho[2,1-b]pyran-1-acetic acid with an IC50 of 0.020 microM, is as potent as sorbinil (IC50 = 0.017 microM) in the crude rat lens aldose reductase assay.     

Synthesis and Antiplatelet and Anticoagulant Activity of Thietane-Containing 2-(5-Bromo-2,4-Dihydro-3-Oxo-1,2,4-Triazolyl-4)Acetate Salts

Pharmaceutical Chemistry Journal - Sulfone II was synthesized via oxidation of ethyl 2-[5-bromo-2,4-dihydro-3-oxo-2-(thietanyl-3)-1,2,4-triazolyl- 4]acetate (I) by H2O2. Hydrolysis of esters I and...     

(6-methyl-2-methylsulfanyl-4-oxo-3,4-dihydro-3-pyrimidinyl)acetic acid and related compounds exhibiting anti-inflammatory activity

Base-promoted hydrolysis of methyl or ethyl esters 1a-c gave the (6-methyl-2-methylsulfanyl-4-oxo-3,4-dihydro-3-pyrimidinyl)- and (5-ethyl-6-methyl-2-methylsulfanyl-4-oxo-3,4-dihydro-3-pyrimidinyl)acetic acids 2a, b. Under the reaction of ester 1a or acid 2a with nucleophilic reagents a series of derivatives 3-7 of acid 2a were synthesized and evaluated for their anti-inflammatory activity. Most of them were found to be more active than acetylsalicylic acid, and compounds 2a, 6a, b, 7a, f were significantly more active than ibuprofen. The compounds exhibiting the best anti-inflammatory activity showed negative inotropic effect.     

Synthesis of some new hydrazone derivatives as biologically active agents

A series of [4-(6H/bromo-4-oxo-2-phenyl-3(4H)-quinazolinyl)phenoxy]acetic acid (1,2-dihydro-1-H/methyl-2-oxo-3H-indol-3-ylidene)hydrazides (VII1-16) were synthesised by condensing 1-H/methyl-5-substituted indoline-2,3-diones with [4-(6H/bromo-4-oxo-2-phenyl-3(4H)-quinazolinyl) phenoxy]acetic acid hydrazides (IV1-2) which in turn were obtained by reacting ethyl [4-(6H/bromo-4-oxo-2-phenyl-3(4H)-quinazolinyl)phenoxy]acetates (III1-2) with hydrazine hydrate. All the synthesised compounds (VIII1-16) were screened for their antibacterial, acetylcholinesterase enzyme inhibitory and antiviral activities.     

Pyridonecarboxylic acids as antibacterial agents. 4. Synthesis and antibacterial activity of 7-(3-amino-1-pyrrolidinyl)-1-ethyl-6-fluoro-1,4 -dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acid and its analogues

The title compounds (28-56) with an amino- and/or hydroxy-substituted cyclic amino group at C-7 were prepared with 1-substituted 7-chloro-, 7-(ethylsulfonyl)-, and 7-(tosyloxy)-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3- carboxylic acids and their ethyl esters (3-7) with cyclic amines such as 3-aminopyrrolidine. The N-1 substituent includes ethyl, vinyl, and 2-fluoroethyl groups. As a result of in vitro and in vivo antibacterial screenings, three compounds, 1-ethyl- and 1-vinyl-7-(3-amino-1-pyrrolidinyl)-6-fluoro- 1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acids (33a and 33b) and 1-vinyl-7-[3-(methylamino)-1-pyrrolidinyl] analogue 34b, were found to be more active than enoxacin (2) and to be worthy of further biological study. Structure-activity relationships are discussed.     

Non-steroidal antiinflammatory agents. Synthesis of novel 2-pyrazolyl-4(3H)-quinazolinones

Four novel series of pyrazolyl-4(3H)-quinazolinones have been prepared through the reaction of 3-aryl-2-hydrazino-4(3H)-quinazolinones with antipyrylazo-derivatives of ethyl acetoacetate, acetylacetone or diethyl malonate. These series of compounds are 3-aryl-2-[1-ethoxycarbonyl-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H - pyrazol-4-yl)hydrazono-2-propylidene]hydrazino-4(3H)-quinazo linones; 3-aryl-2-[4-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl) hydrazono-3-methyl-5-oxo-4,5-dihydro-1H-pyrazol-1-yl]-4(3H)-quinaz olinones; 3-aryl-2-[4-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)azo -3,5- dimethyl-1H-pyrazol-1-yl]-4(3H)-quinazolinones and 3-aryl-2-[4-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl) hydrazono-3,5-dioxo-pyrazolidin-2-yl]-4(3H)-quinazolinones. The antiinflammatory activity of some representatives of the prepared compounds was studied.     

New milrinone analogues: in vitro study of structure-activity relationships for positive inotropic effect,antagonism towards endogenous adenosine,and inhibition of cardiac type III phosphodiesterase

Two mechanisms are responsible for the positive inotropic effect of the cardiotonic drug milrinone, i.e., inhibition of type III cAMP phosphodiesterase (PDE III), and displacement of endogenous adenosine from A(1) inhibitory receptor. Since PDE III inhibition may increase the likelihood of cardiac arrhythmias by increasing cAMP content, our attention focused on the synthesis of new compounds with more pronounced characteristics as adenosine antagonists.In this work, four new milrinone analogues were studied, in comparison with the parent drug, for their effects on the contractility of guinea pig isolated atrial preparations, their ability to antagonize endogenous adenosine at the level of A(1) receptor, and to inhibit the activity of PDE III partially purified from guinea pig heart. The new compounds present various chemical substitutions with respect to the parent drug: in compounds SF397 (methyl 5-cyano-2-methyl-6-oxo-1,6-dihydropyridine-3-carboxylate) and SF399 (benzyl 5-cyano-2-methyl-6-oxo-1,6-dihydropyridine-3-carboxylate), the 4-pyridil moiety of milrinone was replaced with a methoxycarbonyl and a benzyloxycarbonyl group, respectively; the same structural modifications were also associated with the replacement of the cyano-group in 5-position with an acetyl group in compounds SF416 (methyl 5-acetyl-2-methyl-6-oxo-1,6-dihydropyridine-3-carboxylate) and SF419 (benzyl 5-acetyl-2-methyl-6-oxo-1,6-dihydropyridine-3-carboxylate).All the new compounds had a marked positive inotropic effect, most of them also being more active and more potent than milrinone. When their affinity for A(1) receptor was assessed as the displacement of [(3)H] 8-cyclopentyl-1,3-dipropylxanthine ([(3)H]DPCPX) from cardiac membranes, SF397 and SF399 showed affinity (K(i) of about 600 nM) similar to that of milrinone (K(i) 550 nM). By contrast, SF416 and SF419 had very low (K(i) of about 10000 nM) or scarce (K(i) of about 2000 nM) anti-adenosine component, respectively. All the new compounds inhibited PDE III activity, their K(i) values proceeding in the following order: milrinone (3.80 microM) 相似文献   

Synthesis and antiallergic activity of some quinolinones and imidazoquinolinones

A group of 1,4-dihydro-4-oxoquinoline-2- and -3-carboxylic acid esters with nitrogen functionality at the 8-position was synthesized, and 6-oxo-6H-imidazo[4,5,1-ij]quinoline-4- and -5-carboxylic acid esters were elaborated from these. Several of the compounds displayed activity in the rat passive cutaneous anaphylaxis (PCA) test for antiallergic activity. However, PCA activity in this series was accompanied by rat toxicity, as measured by a decrease in percent of normal weight gain over a 2-week period, following a single oral dose.     

Synthesis of 3,4-dihydro-4-oxothieno[2,3-d]pyrimidine-2-carboxylates, a new series of orally active antiallergy agents.

A series of novel 3,4-dihydro-4-oxothieno[2,3-d]pyrimidine-2-carboxylic acid derivatives has been prepared and tested for antiallergenic activity. Members of the series, including both carboxylic acid salts and esters, have been found to exhibit oral activity in the rat passive cutaneous anaphylaxis (PCA) test. Activity is optimized by H or CH3 substitution at the 5 position and lower alkyl groups at the 6 position. Ethyl 6-ethyl-3,4-dihydro-4-oxothieno-[2,3-d]pyrimidine-2-carboxylate and 3,4-dihydro-5-methyl-6-(2-methylpropyl)-4-oxothieno[2,3-d]pyrimidine-2-carboxylic acid dipotassium salt were the most potent of the esters and salts, respectively. Such compounds have been shown to have a duration of action of up to 4 h in the PCA test and to inhibit both histamine release from rat peritoneal mast cells in vitro and allergen-induced bronchospasm in the rat lung.     

Bipyridine cardiotonics: the three-dimensional structures of amrinone and milrinone

The cardiotonic drug milrinone (1,6-dihydro-2-methyl-6-oxo-[3,4'-bipyridine]-5-carbonitrile) is superior to its analogue amrinone (5-amino-[3,4'-bipyridin]-6(1H)-one) by virtue of its greater potency and reduced side effect profile. We confirmed initial reports on the potencies of milrinone and amrinone and found that after intravenous administration to phenobarbital anesthetized dogs, the drugs had cumulative inotropic ED50's of 37 and 1891 micrograms/kg, respectively; relative effects on heart rate and blood pressure were comparable. There are two structural differences between amrinone and milrinone: (1) milrinone has a pyridone 2-methyl substituent and (2) the pyridone 5-amino substituent of amrinone is replaced with a nitrile in milrinone. We confirmed structure-activity studies that indicated that the 2-methyl substituent appears to be primarily responsible for the dramatic difference in the potencies of amrinone and milrinone. A plausible explanation for the effect of the methyl substituent is an altered molecular topology resulting from its steric interaction with the 3',5'-hydrogen atoms. Consequently, we probed the three-dimensional structures of these two compounds by X-ray crystallography. The dihedral angle between the planes formed by the two aromatic rings of amrinone was 1.3 degrees. In marked contrast, the corresponding angle for milrinone was 52.2 degrees. Moreover, 1H NMR studies revealed conformational differences in solution. Whereas the 2-methyl substituent undoubtedly produces some electronic and hydrophobic perturbations in the bipyridine cardiotonic series, the most significant effect, from a global viewpoint, is the altered molecular topology.     

多靶点叶酸拮抗剂—培美曲唑的合成

目的改进多靶点叶酸拮抗剂-培美曲唑的合成工艺。方法以4-溴苯甲酸乙酯和3-丁炔-1-醇为起始原料,经钯（0）催化偶联、氧化、溴代,再同2,4-二氨基吡啶环合,得到4-[2-（2-氨基-4,7-二氢-4-氧代-1H-吡咯并[2,3-d]嘧啶-5-基）乙基]苯甲酸甲酯（4）。4经皂化、酸化,同L-谷氨酸二乙酯部分缩合,得到N-[4-[2-（2-氨基-4,7-二氢-4-氧代-1H-吡咯并[2,3-d]嘧啶-5-基）乙基]苯甲酰基]-L-谷氨酸二甲酯（2）。2和对甲苯磺酸成盐,再经皂化、酸化,得到培美曲唑（pemetrexed,1）。培美曲唑经中和,冷冻干燥,得到临床应用的培美曲唑二钠盐。结果与结论改进了培美曲唑的合成工艺,产物经^1H-NMR、MS确证结构,总收率为39.2%（文献收率36.8%）。     

Chemical synthesis and biological activities of 5-deazaaminopterin analogues bearing substituent(s) at the 5- and/or 7-position(s)

Condensation of cyanothioacetamide (4) with ethyl alpha-(ethoxymethylene)acetoacetate (5b), ethyl 4-ethoxy-2-(ethoxymethylene)-3-oxobutanoate (5c), ethyl 2-(ethoxymethylene)-3-oxo-4-phenylpropanoate (5d) afforded exclusively the corresponding 6-substituted pyridines (6b-d). Cyclization of 4 with 3-carbethoxybutane-2,4-dione (5e) gave 3-cyano-5-(ethoxycarbonyl)-4,6-dimethylpyridine-2(1H)-thione (6e), whereas reaction of 4 with 3-carbethoxy-1-phenylpropane-1,3-dione (5f) yielded two products, 3-cyano-5-(ethoxycarbonyl)-4-methyl-6-phenylpyridine-2(1H)-thione (6f) and the 6-methyl-4-phenyl isomer 6g. The structural assignments for 6f and 6g are made on the basis of 1H and 13C NMR spectral analyses of the 2-(methylthio)nicotinates (7f,g) prepared from 6f and 6g by treatment with MeI/K2CO3. Nicotinates 7b,d-g were converted into their corresponding 2,4-diaminopyrido[2,3-d]pyrimidines 12b,d-g in five steps, via reduction, protection, oxidation, condensation with guanidine, and deprotection. The 7-mono- and 5,7-disubstituted-5-deazaaminopterins (1b,d-g) were prepared from the respective pyrido[2,3-d]pyrimidines 12b,d-g. Preliminary biological studies showed that 7-methyl and 5,7-dimethyl analogues (1b and 1e) were less active than methotrexate against human leukemic HL-60 and murine L-1210 cells in tissue culture. Compound 1e produced an ILS of 71% at 100 mg/kg per day X 5 (ip) in BDF mice inoculated ip with 10(6) L-1210 cells.     

Synthesis and calcium antagonistic activities of fecal metabolites of a new calcium antagonist (+)-(R)-3,4-dihydro-2-[5-methoxy-2-[3-[N-methyl-N- [2-[(3,4-methylenedioxy)phenoxy]ethyl]amino]propoxy]phenyl]-4- methyl-3-oxo-2H-1,4-benzothiazine (SD-3211) in rats

In order to confirm the structure of three fecal metabolites, M-I, M-II and M-III, of a new calcium antagonist, (+)-3,4-dihydro-2-[5-methoxy-2-[3-[N-methyl-N-[2-[(3,4-methylenedioxy) phenoxy]ethyl]amino]propoxy]phenyl]-4-methyl-3-oxo-2H-1,4- benzothiazine (SD-3211), in rats, (+)-3,4-dihydro-2-[5-hydroxy-2-[3-[N-methyl-N-[2- [(3,4-methylenedioxy)-phenoxy]ethyl]amino]propoxy]phenyl]-4-methyl- 3-oxo-2H-1,4-benzothiazine((+)-I), (+)-3,4-dihydro-2-[5-hydroxy-2-[3-[N- [2-[(3,4-methylenedioxy) phenoxy]ethyl]amino] propoxy]-phenyl]-4-methyl-3-oxo-2H-1,4-benzothiazine((+)-II) and (+)-3,4-dihydro-2-[5-methoxy-2-[3-[N-[2-[(3,4-methylenedioxy) phenoxy]ethyl]amino]propoxy]phenyl]-4-methyl-3-oxo-2H-1,4- benzothiazine((+)-III) were synthesized. Compounds (+)-I, (+)-II and (+)-III were identified with the fecal metabolites M-I, M-II and M-III, respectively. The calcium antagonistic activities of (+)-I, (+)-II and (+)-III were examined.     

Synthesis and biological studies of triazolo-/thiadiazolo-benzoxazines

Diethyl bromomalonate (2) with an equimolar amount of 2-aminophenol (1) in the presence of sodium fluoride undergoes a cyclization reaction to form 2H,4H-2-ethoxycarbonyl-3,4-dihydro-3-oxo-1,4-benzoxazine (3). Furthermore, compound 3 undergoes a condensation reaction with hydrazine hydrate in the presence of methanol to yield 2H,4H-2-hydrazinocarbonyl-3,4-dihydro-3-oxo-1,4-benzoxazine (4), which on further reaction with aryl isothiocyanates gave 2H,4H-2-[ (4'-substituted)-phenylthiosemicarbazino]-carbonyl-3,4-dihydro-3-oxo-1,4-benzoxazine (5). Compound 5 on treatment with NaOH, cone. H2SO4 and diethylmalonate (6). afforded 2H,4H-2-[2'H-3'-thioxo-4'-substituted phenyl-1',2',4'-triazole-5-yl]- 3,4-dihydro-3-oxo-1,4benzoxazine (7). 2H,4H-2-[2'-amino-(substituted)-phenyl-1,3',4'-thiadiazol-5-yl]-3,4-dihydro-3-oxo-1,4-benzoxazine (8) and 2H,4H-2-[5'H-5'-dihydro-2'-thioxo-3'-phenyl-4',6'-dioxo-1,3-diazine]-aminocarbonyl-3,4-dihydro-3-oxo-1,4-benzoxazine (9), respectively. The synthesized compounds were investigated for their antibacterial activities against Gram positive as well as Gram negative bacteria with ampicillin trihydrate as standard drug. Structures have been elucidated on the basis of spectral and chemical analyses.     

Novel cAMP PDE III inhibitors: 1,6-naphthyridin-2(1H)-ones.

Two series of medorinone (3) analogs were prepared by modifications at C(2) and C(5). The C(2)-series was prepared from 2-chloro-5-methyl-1,6-naphthyridine (4) by replacement of the chloro group with various nucleophiles. The C(5)-series was prepared from 5-acyl-6-[2-(dimethylamino)-ethenyl]-2(1H)-pyridinone (11), 5-bromo-1,6-naphthyridin-2(1H)-one (17), and 1,3-diketones 19 and 27. 1,6-Naphthyridin-2(1H)-ones are novel inhibitors of cAMP PDE III. Modification of the carbonyl group of 3 or N-methylation at N(1) resulted in a dramatic loss of enzyme activity. Absence of the C(5)-methyl group of medorinone (3) or its shift to C(3) or C(7) also resulted in reduced activity. Substitution at C(3) also diminished activity. However, substitution at C(5) by a wide variety of substituents led to improvement of enzyme activity and several C(5)-substituted analogs were more potent than milrinone.     

Benzoyl ring halogenated classical 2-amino-6-methyl-3,4-dihydro-4-oxo-5-substituted thiobenzoyl-7H-pyrrolo[2,3-d]pyrimidine antifolates as inhibitors of thymidylate synthase and as antitumor agents

In an attempt to circumvent resistance to and toxicity of clinically used folate-based thymidylate synthase (TS) inhibitors that require folylpoly-gamma-glutamate synthetase (FPGS) for their antitumor activity, we designed and synthesized two classical 6-5 ring-fused analogues, N-[4-[(2-amino-6-methyl-3,4-dihydro-4-oxo-7H-pyrrolo[2,3-d]pyrimidin-5-yl)thio]-2'-fluorobenzoyl]-l-glutamic acid (4) and N-[4-[(2-amino-6-methyl-3,4-dihydro-4-oxo-7H-pyrrolo[2,3-d]pyrimidin-5-yl)thio]-2'-chlorobenzoyl]-l-glutamic acid (5), as TS inhibitors and antitumor agents. The key intermediates in the synthesis of these classical analogues were the mercaptans 10 and 11, which were obtained from the corresponding nitro compounds 6 and 7 respectively, by reduction of the nitro groups followed by diazotization of the amines. The syntheses of analogues 4 and 5 were achieved via the oxidative addition of the sodium salt of ethyl 2-halo-substituted-4-mercaptobenzoate (16 or 17) to 2-amino-6-methyl-3,4-dihydro-4-oxo-7H-pyrrolo[2,3-d]pyrimidine (18) in the presence of iodine. The esters obtained from the reaction were deprotected and coupled with diethyl-l-glutamate followed by saponification. Compounds 4 and 5 were both more potent inhibitors of human TS (IC(50) values of 54 and 51 nM, respectively) than were PDDF and the clinically used ZD1694 and LY231514. Compounds 4 and 5 were not substrates for human FPGS up to 250 muM. In addition, 4 and 5 were growth inhibitory against CCRF-CEM cells as well as a number of other tumor cell lines in culture, and protection studies established TS as the principal target of these analogues.     

Synthesis of thiazolo[4,5-d]pyrimidine derivatives as potential antimicrobial agents

In this study, we report the synthesis and antimicrobial evaluation of several new thiazolo[4,5-d]pyrimidine derivatives, namely 7-substituted amino-5-methyl-3-phenylthiazolo[4,5-d]pyrimidine-2(3H)-thiones 4a-e, 8, 13, 15, ethyl 2-cyano-2-(7-substituted-5-methyl-3-phenylthiazolo [4,5-d]-pyrimidin-2(3H)-ylidene)acetates 5a-b, 2-(7-substituted-5-methyl-3-phenylthiazolo[4,5-d]pyrimidin-2(3H)-ylidene)malononitriles 6a-b, 5-methyl-7-morpholino-3-phenylthiazolo[4,5-d] pyrimidine-2(3H)-one 7, and 7-[4-(1-substituted-5-phenyl-4,5-dihydro-1H-pyrazolin-3-yl)anilino]-5-methyl-3-phenylthiazolo[4,5-d]pyrimidine-2(3H)-thiones 10-12. Some of the tested compounds were more active against C. albicans than E. coil and P. aeruginosa, and all were inactive against S. aureus.