Hyperactivity induced by tetrahydroisoquinoline derivatives injected into the nucleus accumbens.

Several derivatives of tetrahydroisoquinoline were injected bilaterally into the nucleus accumbens of rat 2 h after a nialamide pretreatment and activity recorded in cages fitted with photocells. 1,2,3,4-Tetrahydroisoquinoline, 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline, 1,2,3,4-tetrahydro-6,7-dihydroxy-1-(3,4-dihydroxybenzyl)-isoquinoline (tetrahydropapaveroline) and 6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline caused virtually no change in locomotor activity and 2-methyl-1,2,3,4-tetrahydroisoquinoline and 2-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline caused only modest hyperactivity responses. However, 3-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline and 3-methyl-6,7-methylenedioxy-1,2,3,4-tetrahydroisoquinoline were both shown to markedly increase activity in a dose-dependent manner. Of these two compounds, the 3-methyl-6,7-methylenedioxyderivatives was most active and equalled the effectiveness of dopamine. The responses to dopamine and to 3-methyl-6,7-methylenedioxy-1,2,3,4-tetrahydroisoquinoline were both threshold at 3.125 mug and maximum at 50 mug. Both effects developed within 1-2 h and persisted for at least 6 h. The hyperactivity induced by dopamine was antagonised in a dose-dependent manner by haloperidol: propranolol and aceperone were without effect. Similar results were obtained for these blocking agents against the responses to 3-methyl-6,7-methylenedioxy-1,2,3,4-tetrahydroisoquinoline and 2-methyl-1,2,3,4-tetrahydroisoquinoline but aceperone and propranolol, in addition to haloperidol, were shown to inhibit the hyperactivity induced by 3-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline.     

1-［1-(6-甲氧基-2-萘基)乙基］-2-(4-硝基苄基)-6,7-二甲氧基-1,2,3,4-四氢异喹啉氢溴酸盐的光降解产物研究

研究1-［1-(6-甲氧基-2-萘基)乙基］-2-(4-硝基苄基)-6,7-二甲氧基-1,2,3,4-四氢异喹啉氢溴酸盐(编号P91024)遇光后颜色变暗的光降解产物。采用HPLC-MS及波谱分析鉴定光降解产物的化学结构，并经有机反应合成对照验证。P91024光降解的3个主要产物分别为溴化N-(4-硝基苄基)-6,7-二甲氧基-3,4-二氢异喹啉、1-［1-(6-甲氧基-2-萘基)乙基］-6,7-二甲氧基-1,2,3,4-四氢异喹啉和2-异丙基-6-甲氧基萘。     

Synthesis and Comparative Inotropic Effects of Several Isoquinoline Alkaloids

Pharmaceutical Chemistry Journal - Compounds 3a [1-(3′,4′-methylenedioxyphenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline] and 3b...     

Synthesis of higenamine,A cardiotonic principle of aconite root

Higenamine (I), a cardiotonic principle of Aconite root, was synthesized from 4-methoxy-phenylacetic acid (II) and β-(3, 4-dimethoxyphenyl)-ethylamine (IV). Condensation ofIV with 4-methoxyphenylacetyl chloride (III) was followed by cyclodehydration yielding 1-(4′-methoxybenzyl)-6,7-dimethoxy-3,4-dihydroisoquinoline (VI). Reduction ofVI to 1, 2, 3, 4-tetrahydroisoquinoline (VII) and subsequent demethylation provided desired product higenamine, 1-(4′-hydroxybenzyl)-6, 7-dihydroxy-1, 2, 3, 4-tetrahydroisoquinoline.     

Synthesis and pharmacological evaluation of 1-oxo-2-(3-piperidyl)-1,2,3,4- tetrahydroisoquinolines and related analogues as a new class of specific bradycardic agents possessing I(f) channel inhibitory activity

A series of 1-oxo-2-(3-piperidyl)-1,2,3,4-tetrahydroisoquinolines and related analogues were prepared and evaluated for their bradycardic activities in isolated right atrium and in anesthetized rats. (+/-)-6,7-Dimethoxy-2-[1-[3-(3,4-methylenedioxyphenoxy)propyl]-3-piperidyl]-1,2,3,4-tetrahydroisoquinoline (4) was chosen as a lead, and structural modifications were performed on the tetrahydroisoquinoline ring and the terminal aromatic ring. The modifications on the tetrahydroisoquinoline ring revealed that the 1-oxo-1,2,3,4-tetrahydroisoquinoline ring system was optimum structure for both in vitro potency and in vivo efficacy. Furthermore, methoxy, ethoxy, and methoxycarbonyl groups were identified as preferable substituents on the terminal aromatic ring. One of the 1-oxo-1,2,3,4-tetrahydroisoquinoline derivatives, (R)-10a, was further evaluated for its bradycardic activity and inhibitory activity against I(f) currents. Compound (R)-10a demonstrated potent bradycardic activity in rats with minimal influence on blood pressure after oral administration. The compound also showed inhibition of I(f) currents (IC(50) = 0.32 muM) in guinea pig pacemaker cells.     

莲子心生物碱的研究——Ⅳ.莲心碱的全合成

本文报导了莲心碱(Ⅰ)全合成的研究。(1)合成了1-(3′-溴-4′-苄氧基)苄基-2-甲基-6,7-二甲氧基-1,2,3,4-四氢异喹啉(Ⅷ)和1-(4′-苄氧基)苄基-2-甲基-6-甲氧基7-羟基-1,2,3,4-四氢异喹啉(XV).(2)1-(3′-溴-4′-苄氧基)苄基-6,7-二甲氧基-1,2,3,4-四氢异喹啉(Ⅵ)和1-(4′-苄氧基)苄基-6-甲氧基-7-乙酰氧基-1,2,3,4-四氢异喹啉(ⅩⅢ)借d-和1-DPT-酒石酸各自拆分为其对映体。D-(-)-Ⅵ和L-(+)-Ⅵ以甲酸和甲醛甲基化分别生成D-(-)-Ⅷ和L-(+)-Ⅷ。D-(+)-;ⅩⅢ和L-(-)-ⅩⅢ经N-甲基化后再进行水解卽得D-(-)-ⅩⅤ和L-(+)+ⅩⅤ。(3)D-(-)-Ⅷ和D-(-)-ⅩⅤ在吡啶中有铜粉和碳酸钾存在下进行Ullmann反应,反应物经氧化鋁柱层析可分得一油状物,此油状物经盐酸水解得黄色无定形固体,后者与过氯酸生成过氯酸盐结晶,其理化性质均与天然莲心碱过氯酸盐相同。(±)-Ⅷ和(±)-ⅩⅤ在相似的条件下缩合则生成(±)-莲心碱。     

Synthesis of 1-substituted analogues of trimetoquinol possessing differential and selective beta-adrenergic properties.

The synthesis of the 1,1-disubstituted tetrahydroisoquinoline analogues, 1-methyl-1-(3,4,5-trimethoxybenzyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline hydrochloride (2) and 1-benzyl-1-(3,4,5-trimethoxybenzyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline hydrochloride (3), is described. The profile of beta-adrenergic activity for these analogues was determined and compared to that of trimetoquinol (1) in isolated guinea pig atrial, tracheal, and rat adipocyte preparations. Unexpected selective beta1-blocking activity in guinea pig trachea was noted with analogue 3. With the exception of 2 in guinea pig atria, 2 and 3 did not possess any beta-stimulant activity. Substitution at the 1 position of trimetoquinol (1) has revealed qualitative differences in beta-adrenergic activity.     

Umsetzungen des 1,2-Dihydro-2-methyl-papaverinols in verdünnter Essigsäure

Reactions of 1,2-Dihydro-2-methyl-papaverinol in dilute Acetic Acid When 1,2-dihydro-2-methyl-papaverinol (II) is treated with 2% acetic acid, 3,4-dihydro-6,7-dimethoxy-3-(3,4-dimethoxy-α-hydroxy-benzyl)-2-methyl-isoquinolinium-ion (IX), 9-hydroxylaudanosin (I), 6,7-dimethoxy-2-methyl-isoquinolinium-ion (III b) and veratraldehyd (IV) are formed.     

Cholinergic effects of molecular segments of apomorphine and dopaminergic effects of N,N-dialkylated dopamines.

The hydrochlorides of molecular segments of apomorphine [2-(3',4'-dihydroxybenzyl)-1,2,3,4-tetrahydroisoquinoline, 2-(3'4'-dihydroxybenzyl)piperidine, and 1,2,3,4-tetrahydroisoquinoline with their respective N-methyl and N-n-propyl homologs] and N,N-dialkylated dopamine compounds were synthesized and studied for (1) LD50 in intact mice; (2) stereotypy in intact mice; (3) curving of the body in unilaterally caudectomized mice; (4) rotation in 6-hydroxydopamine-lesioned rats, and (5) activation of adenylate cyclase in homogenates of mouse caudate nuclei. Instead of dopaminergic effects 1-(3',4'-dihydroxybenzyl)-2-methyl-1,2,3,4-tetrahydroisoquinoline and 2-methyl-1,2,3,4-tetrahydroisoquinoline showed cholinergic ones. These effects were blocked in atropine-pretreated animals. Of the N,N-dialkylated dopamine compounds synthesized, the N-n-propyl-N-n-butyldopamine ranked in all tests as the strongest dopamine-receptor agonist and N-methyl-N-n-propyldopamine as the weakest. In contrast, N,N-dimethyldopamine and 1-(3,4-dihydroxyphenylethyl)piperidine showed no dopaminergic effects. The effectiveness of the dopaminergic agonists depended on the length of the N-alkyl substituents suggesting interactions with hydrophobic regions of the receptor site.     

Inhibitory effects of tetrandrine and related synthetic compounds on angiogenesis in streptozotocin-diabetic rodents.

Structure-activity relationships of tetrandrine, isolated from a Kampo medicine, Stephania tetrandrae S. MOORE (root), and related synthetic compounds, were investigated in in vitro fetal bovine serum (FBS)-stimulated angiogenesis of cultured choroids in streptozotocin-diabetic Wistar rats, and air-pouch granuloma angiogenesis in vivo in diabetic mice. Tetrandrine, KS-1-1 (6,7-dimethoxy-1-[[4-[5-(6,7-dimethoxy-2-methyl-1,2,3,4-tetrahydroiso quinolinyl)methyl-2-methoxy]phenoxy]benzyl]-2-methyl-1,2,3,4-tetrahyd roisoquinoline), and KS-1-4 (6,7-dimethoxy-1-[[4-[4-(6,7-dimethoxy-2-methyl-1,2,3,4-tetrahydroiso quinolinyl)methyl]phenoxy]benzyl]-2-methyl-1,2,3,4-tetrahydroisoquino line), potently inhibited choroidal angiogenesis and air-pouch granuloma angiogenesis in the diabetic state. Their inhibitory effects on diabetic choroids were greater than those on normal choroids. Among these compounds, KS-1-4 inhibited only diabetic angiogenesis. These compounds significantly inhibited FBS-stimulated tube formation in vascular endothelial cells from normal rats. Tetrandrine and KS-1-4, but not KS-1-1, inhibited vascular endothelial growth factor- and platelet-derived growth factor-BB-stimulated angiogenesis in normal choroids. The bis[tetrahydroisoquinoline] moiety, connected by oxy-bis[phenylenemethylene] and 2,2'-dimethyl groups in tetrandrine, contributes to the inhibition of diabetic choroidal angiogenesis. KS-1-4 may be a candidate for anti-choroidopathy and retinopathy drugs in the diabetic state.     

Synthesis and biological activity of 2- and 4-substituted 6,7-dihydroxy-1,2,3,4-tetrahydroisoquinolines.

Various 2- and 4-substituted 6,7-dihydroxy-1,2,3,4-tetrahydroisquinolines were synthesized and evaluated as substrates and inhibitors of catechol O-methyltransferase (COMT). In addition, these compounds were tested for their ability to release norepinephrine-3H from mouse hearts in vivo. Methyl substituents in the 2 and/or 4 positions of 6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline had little effect on the interaction of these molecules with COMT. In general, the substrate kinetic (Km, Vmax) and inhibitory kinetic (Kis) properties toward COMT were similar for each of these compounds. In contrast, norepinephrine depleting activity showed more strict structural requirements. Methyl substituents in the 2 or 4 positions of the parent compound, 6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, eliminated the norepinephrine depleting activity. The interesting exception was 6,7-dihydroxy-2,2-dimethyl-1,2,3,4-tetrahydroisoquinolinium iodide, which was found to be more active than the parent molecule as a depleter of norepinephrine from mouse hearts.     

1-(α-萘甲基)2-甲基-6,7-二甲氧基-四氢异喹啉对大鼠α-肾上腺素受体的阻断作用

1—(α—萘甲基)2—甲基—6,7—二甲氧基—四氢异喹啉;;α—肾上腺素受体;;肛尾肌输精管     

Synthesis and biological evaluation of a tetrahydroisoquinoline derivative possessing selective beta2-adrenergic agonist activity.

This paper reports the synthesis of 4-(3,4,5-trimethoxybenzyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (2) and 2-(3,4-dihydroxyphenyl)-3-(3,4,5-trimethoxyphenyl)propylamine (3). The biological activity of these agents relative to that of trimetoquinol (1) in guinea pig atria and guinea pig trachea is reported. The relative activities in relaxation of guinea pig trachea is 1 greater than 2 greater than 3 while in the chronotropic response in guinea pig atria the relative order of activity is 1 greater than 3 greater than 2.     

Synthesis and anticonvulsant properties of tetrahydroisoquinoline derivatives

As a follow up of our previous structure-activity relationship and molecular modeling studies, we synthesized a novel series of 1-aryl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline derivatives as potential non-competitive AMPA receptor antagonists. When tested for their ability to prevent sound-induced seizures in DBA/2 mice, some of these novel compounds showed high anticonvulsant potency.     

The chromatographic data in QSAR assay of TIQs derivatives with beta2-adrenergic activity

We performed QSAR analysis of beta2-adrenergic activity and chromatographic data of 4,6,8-trihydroxy-, 6,7-dihydroxy- and 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline derivatives. TLC plates (silica gel NP 60F(254) and silica gel RP2 60F(254) silanised precoated), impregnated with solutions of analogues of the selected amino acids were used as beta2-agonistic and antagonistic interaction models. QSAR analysis of the beta2-adrenergic activity and the chromatographic data of the solutes were made. A correlation between biological data and behaviour of the examined compounds in a chromatographic modifiable environment (S1-S3) was investigated by the linear regression analysis method.     

Selective and potent beta 2-adrenoceptor agents within the tetrahydroisoquinoline class: effect of methyl substitution at the benzylic carbon of the 1-(3,4,5-trimethoxybenzyl) group of trimetoquinol

A systematic series of methyl (2 and 3) and dimethyl (4) analogues of trimetoquinol (1) were synthesized and evaluated for their beta 1 (atria) and beta 2 (trachea) and adrenoceptor activities. Structural assignments for the erythro (2) and the threo (3) diastereoisomers of 1-(3,4,5-trimethoxy-alpha-methylbenzyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline were based on NMR spectra of the 6,7-dibenzyl precursors 15 and 16, respectively, and on the synthetic derivatives of cis- and trans-13-methyl-2,3-bis(benzyloxy)-9,10,11-trimethoxytetrahydroprotoberberine (18 and 17). The rank order of beta 2-agonist activity for these compounds was 3 greater than 1 greater than 2 greater than 4. The rank order of activity as beta 1 agonists on the guinea pig atria is 1 greater than 3 greater than 2, and 4 was inactive. The methylated analogues show selectivity for beta 2 receptors in our preliminary pharmacological studies. The threo isomer 3 is the most potent and selective beta 2 stimulant reported to date in the tetrahydroisoquinoline class.     

Determination of l-Dopa Content and Other Significant Nitrogenous Compounds in the Seeds of Seven Mucuna and Stizolobium Species in China

Seven samples of seeds from the genera Mucuna and Stizolobium (Leguminosae) were collected throughout southern China. HPLC analysis revealed l-dopa concentrations ranging from 3.9 to 6.2%. The seeds of the most commercially available species, S. pruriens var. utilis, collected biweekly during the fruit period, were also assayed using the same method, and their l-dopa concentrations were found to vary between 4.2 to 10.6%. Other nitrogenous compounds, which are significant in chemotaxonomy between the two plant types or have potential influence on analysis of l-dopa in the seeds were identified as stizolamine 3,4-dihydro-5-hydroxymethyl-4-methyl-3-oxopyrazinyl-guanidine), l-3-carboxy-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, and its derivatives.     

Synthesis and biological evaluation of fragmented derivatives of tetrahydroisoquinolines. 2. Trimetoquinol studies.

The synthesis of N-(3',4',5'-trimethoxyphenylethyl)-3,4-dihydroxyphenylethylamine (2) and 1-(3,4,5-trimethoxybenzyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (1) is presented. Comparative pharmacological effects of the optical isomers of 1 and compound 2 are reported in guinea pig atria, rat adipose tissue, guinea pig trachea, and guinea pig aortic strip preparations. In the beta-adrenoreceptor preparations, (-)-1 was shown to be more potent than (+)-1 or 2. Racemic 1 and 2 were shown to have equal alpha-antagonist properties in the inhibition of norepinephrine-induced contractions of guinea pig aorta.     

Removal of the Pyrrolidine Group by Dehydrogenation of a 4-Pyrrolidin-2-yl-tetrahydroisoquinoline

Dehydrogenation of 6,7-dimethoxy-1-methyl-4-(N-methyl-pyrrolidin-2-yl)-3,4-dihydroisoquinoline ( 9 ) by Pd/C in tetraline leads to dehydrogenated products, rearrangement, and elimination of the pyrrolidine group mainly as N-methylpyrrolidine (Scheme 3).     

Synthesis and evaluation of the biological activities of some 3-{[5-(6-methyl-4-aryl-2-oxo-1,2,3,4-tetrahydropyrimidin-5-yl)-1,3,4-oxadiazol-2-yl]-imino}-1,3-dihydro-2H-indol-2-one derivatives

Reaction of ethyl-6-methyl-2-oxo-4-aryl-1,2,3,4-tetrahydropyrimidin-5-carboxylates (1a-i) with hydrazine hydrate yielded 6-methyl-2-oxo-4-aryl-1,2,3,4-tetrahydropyrimidin-5-carbohydrazides (2a-i). These products, on reaction with cyanogen bromide, gave 5-(5-amino-1,3,4-oxadiazol-2-yl)-6-methyl-4-aryl-3,4-dihydropyrimidin-2 (1H)-ones (3a-i). The resultant aminooxadiazolylpyrimidinones were condensed with isatin to obtain various 3-{[5-(6-methyl-4-aryl-2-oxo-1,2,3,4-tetrahydropyrimidin-5-yl)-1,3,4-oxadiazol-2-yl]-imino}-1,3-dihydro-2H-indol-2-ones (4a-i). These products were characterized by IR, 1H NMR, mass spectra and elemental analysis. Products (4a-i) revealed promising antibacterial, antifungal and antioxidant activity.