Hydrolysis of 7,7-Substituted Derivatives of 3-tert-Butyl-3,4-dihydro-2H-thiazolo-[3,2-a][1,3,5]triazin-6(7H)-one

Alkaline hydrolysis of 3-tert-butyl-7,7-bis(hydroxymethyl)-3,4-dihydro-2H-thiazolo[3,2-a][1,3,5]-triazin-6(7H)-one can occur in three directions: with cleavage of the tetrahydrotriazine ring, with cleavage of the thiazolidine ring, and also with opening of both rings. Depending on the process conditions, either the hydrolysis product corresponding to the first direction or the hydrolytic decomposition products corresponding to the second and third directions can be obtained in preparative quantities. Hydrolysis of 3,3′-di-tert-butyl-3′,4′-dihydro-2′ H-spiro[(perhydro-1,3-oxazine)-5,7′-thiazolo[3,2-a][1,3,5]triazin]-6′-one in (NH₄)₂CO₃ solution occurs in two steps: in the first step, cleavage of the tetrahydrotriazine ring occurs; and in the second step, opening of the perhydrooxazine ring occurs. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1089–1097, July, 2005.     

Synthesis and selected properties of N-substituted pyrrolo[2,1-c]-1,3-diazacycloalkano[1,2-a]pyrazinones

The reactions of methyl α-(2-formyl-1H-pyrrol-1-yl)carboxylates with N-substituted aliphatic 1,2-, 1,3-, and 1,4-diamines afford new pyrrole-containing heterocyclic systems: 1,2,3,10b-tetrahydroimidazo[1,2-a]pyrrolo[2,1-c]pyrazin-5(6H)-ones, 1,3,4,11b-tetrahydro-2H-pyrrolo[2′,1′:3,4]pyrazino[1,2-a]pyrimidin-6(7H)-ones, and 1,2,3,4,5,12b-hexahydro-pyrrolo[2′,1′:3,4]pyrazino[1,2-a][1,3]diazepin-7(8H)-ones. The reduction of these compounds with different reagents was studied.     

[3,4]-annulated pyrroles 1. Polynuclear heterocyclic systems based on pyrrolo[3,4-d]pyrimidine-2,4-dione

The intramolecular electrophilic substitution in 6-functionalized 1,3-dimethyl-1H-pyrrolo[3,4-d]pyrimidine-2,4(3H,6H)-diones was used for the synthesis of pyrimido[4′,5′:3,4]-pyrrolo[1,2-a]quinoxaline-8,10(7H,9H)-dione, pyrimido[4′,5′:3,4]pyrrolo[2,1-c][1,2,4]benzo-triazine-8,10(7H,9H)-dione, and 2H-pyrimido[4′,5′:3,4]pyrrolo[1,2-a]indole-2,4,11(1H, 3H)-trione derivatives. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2180–2185, December, 2006.     

New heterocyclic structures. [1,2,5]Thiadiazolo[3′,4′:4,5]pyrimido-[2,1-b][1,3]thiazine and thiazolo[3,2a][1,2,5]thiadiazolo[3,4-d]pyrimidine

Derivatives of two new molecular structures, namely, 7,8-dihydro-6H,10H-[1,2,5]thiadiazolo[3′,4′:4,5]pyrimido[2,1-b][1,3]thiazin-10-one and 6,7-dihydro-9H-thiazolo[3,2-a][1,2,5]thiadiazolo[3,4-d][pyrimidin-9-one, and derivatives of N-substituted sulfamic acid, namely, (8-amino-3,4-dihydro-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-on-7-yl)sulfamic acid and (7-amino-2,3-dihydro-5H-thiazolo[3,2-a]pyrimidin-5-on-6-yl)sulfamic acid, were separated out as by-products in the reduction reaction of 8-amino-3,4-dihydro-7-nitroso-2H,6H-pyrimido[2,1- b][1,3]thiazin-6-one and 7-amino-2,3-dihydro-6-nitroso-5H-thiazolo[3,2-a]pyrimidin-5-one derivatives, respectively, with sodium hydrosulfite. A mechanism of reaction, which hypothesizes the action of sodium hydrosulfite in an asymmetic form, is proposed. The results of single-crystal X-ray investigation on 7,8-dihydro-6H,10H-[1,2,5]thiadiazolo[3′,4′:4,5]pyrimido[2,1-b][1,3]thiazin-10-one (R = 0.032 for 863 reflections) and (8-amino-3,4-dihydro-2H,6H-pyrimido[2,1-b]- [1,3]thiazin-6-on-7-yl)sulfamic acid, sodium salt (R = 0.028 for 3507 reflections) are reported.     

5,6-Dihydro-4H-pyrrolo[1,2-a][1,4]benzodiazepine-4,4-diacetic acid diethyl ester,an useful synthon for the synthesis of new polycyclic nitrogen systems of pharmacological interest

This report describes the synthesis of derivatives of two nitrogen tetracyclic ring systems, respectively 9H,11H-pyrimido[4,3-c]pyrrolo[1,2-a][1,4]benzodiazepine and spiro[piperidine-4,4′-[4H]pyrrolo[1,2-a][1,4]-benzodiazepine], by the use of the diethyl ester of 5,6-dihydro-4H-pyrrolo[1,2-a][1,4]benzodiazepine-4,4-diacetic acid as a synthon. This compound was obtained by condensation of 1-(2-aminomethylphenyl)-1H-pyrrole with diethyl 1,3-acetonedicarboxylate in acid medium. Pyrimidopyrrolobenzodiazepine derivatives were obtained by treating either the pyrrolobenzodiazepine 4,4-diacetate or the related 4-methyl-4-acetate with phenylisocyanate in boiling diethyl ether in the presence of sodium metal. The structure of 12,13-dihydro-11,13-dioxo-12-phenyl-9H,11H-pyrimido[4,3-c]pyrrolo[1,2-a][1,4]benzodiazepine, a product formed by loss of an acetate unit when 5,6-dihydro-4H-pyrrolo[1,2-a][1,4]benzodiazepine-4,4-diacetate, sodium metal and phenyl-isocyanate reacted in boiling xylene, was proved by catalytic reduction to 11,13-dioxo-12-phenyl-12,13,14,14a-tetrahydro-9H,11H-pyrimido[4,3-c]pyrrolo[1,2-a][1,4]benzodiazepine, which was synthesized by unambiguous pathway via 5,6-dihydro-4H-pyrrolo[1,2-a][1,4]benzodiazepine-4-acetate. The 2,6-dioxospiro[piperidine-4,4′-[4H]pyrrolo[1,2-a][1,4]benzodiazepine] derivatives were synthesized from the N-BOC derivative of 5,6-dihydro-4H-pyrrolo[1,2-a][1,4]benzodiazepine-4,4-diacetic acid diethyl ester, by hydrolysis followed by treatment with 2 equivalents of 1,1′-carbonyldiimidazole (CDI) and then with aniline or benzylamine. Removal of BOC from the N-phenyl-2,6-dioxopiperidine derivative was obtained by heating the related spiroderivative in toluene in the presence of p-toluenesulphonic acid. Similar reaction failed when the N-benzyl-2,6-dioxopiperidine analog was used as substrate.     

Proton magnetic resonance studies of compounds with bridgehead nitrogen atoms: XXXII—The 1H n.m.r. spectra and stereochemistry of 4-aryl-1,6,7,11b-tetrahydro-2H,4H-[1,3]oxazino[4,3-a]isoquinoline, 4-aryl-1,2,6,7,12,12b-hexahydro-4H-[1,3]oxazino[3′,4′:1,2]pyrido[3,4-b]indole and of related systems

cis(4-H,11b-H)-4-Aryl-1,6,7,11b-tetrahydro-2H,4H-[1,3]oxazino [4,3-a]isoquinoline and the related thiazino compound preferentially adopt in solution the O (or S) inside cis-conformation in contrast to cis(1-H,4a-H)-1-arylperhydropyrido[1,2-c][1,3]oxazine which adopts the trans fused conformation. 1-(β-Hydroxy-ethyl)-1,2,3,4-tetrahydro-β-carboline condenses with benzaldehyde to give the 1,3-oxazine derivative rather than the dimeric structure reported in the literature.     

2-[3-(Trifluoromethyl)phenyl]furo[3,2-b]pyrroles: synthesis and reactions

The synthesis and reactions of methyl 2-[3-(trifluoromethyl)phenyl]-4H-furo[3,2-b]pyrrole-5-carboxylate (1a) are described. Upon reaction with methyl iodide, benzyl chloride, or acetic anhydride, this compound gave N-substituted products 1b-d. By hydrolysis of compounds 1a-c, the corresponding acids 2a-c were formed, or by reaction with hydrazine-hydrate, the corresponding carbohydrazides 3a-c were formed. By heating 2-[3-(trifluoromethyl)phenly]-4H-furo[3,2-b]pyrrole-5-carboxylic acid (2a) in acetic anhydride, 4-acetyl-2-[3-(trifluoromethyl)phenyl]furo[3,2-b]pyrrole (4) was formed. By hydrolysis of 4, 2-[3-(trifluoromethyl)phenyl]-4H-furo[3,2-b]pyrrole (5a) was formed, and reactions with methyl iodide or benzyl chloride gave N-substituted products 5b-c. The reaction of 4 with dimethyl butynedioate gave substituted benzo[b]furan 6. Compound 3a reacted with triethyl orthoesters giving 7a-c, which afforded with phosphorus (V) sulphide the corresponding thiones 8a-c. The thiones 8a-c reacted with hydrazine hydrate to form hydrazine derivatives 9a-c. The reaction of triethyl orthoformiate with compounds 9a-c led to furo[2′,3′: 4,5]pyrrolo[1,2-d][1,2,4]triazolo[3,4-f][1,2,4]triazines 10a-c. Hydrazones 11a-c were formed from 3a-c and 5-[3-(trifluoromethyl)phenyl]furan-2-carboxaldehyde. The effect of microwave irradiation on some condensation reactions was compared with “classical” conditions. The results showed that microwave irradiation shortens the reaction time while affording comparable yields.     

A simple synthesis of heterocyclic ring systems containing the 1,3-oxazine nucleus

An easy, one-step conversion of aldol adducts 1 into spiro-derivatives of partially hydrogenated [1,3]oxazino[2,3-a]isoquinoline 5 , [1,3]oxazino[2,3-a]phthalazine 6 and [1,3]oxazino[3,2-a]quinoline 7 is reported.     

Synthesis of Benzofuro[3,2-e][1,4]diazepines

A synthesis of 4-N-oxides and of 3-hydroxy derivatives of 1,3-dihydro-2H-benzofuro[3,2-e][1,4]diazepin-2-ones and of 2,3-dihydro-1H-benzofuro[3,2-e][1,4]diazepines is described. Condensation of 2-acetyl- and 2-benzoyl-3-ethoxycarbonylaminobenzofurans with acrylonitrile gave derivatives of 1,2-dihydro- and of 1,2,3,4-tetrahydrobenzofuro[3,2-b]pyridine.     

New heterocyclic structures. [1,3]Thiazino[3,2-a]purine and [1,2,3]triazolo[4,5-d][1,3]thiazino[3,2-a]pyrimidine

Derivatives of two new molecular structures, namely, [1,3]thiazino[3,2-a]purine and [1,2,3]triazolo[4,5-d]-[1,3]thiazino[3,2-a]pyrimidine, were synthesized together with other heterocyclic compounds. Retrosynthetic analysis of their molecular skeletons suggested a simple way of obtaining 3,4-dihydro-7,8-diamino-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-one, which is a useful intermediate for their synthesis. This intermediate and the thiazole homologue were obtained directly by reaction of 5,6-diamino-2,3-dihydro-2-thioxo-4(lH)-pyrimidi-none with 1,3- or 1,2-dibromoalkane, respectively.     

The reaction of isoquinoline and dimethyl acetylenedicarboxylate with 1,2- and 1,4-benzoquinones: a novel synthesis of spiro[1,3]oxazino[2,3-a]isoquinolines

The 1,4-dipolar intermediate generated by the addition of isoquinoline to dimethyl acetylenedicarboxylate is trapped by 1,2- and 1,4-benzoquinones to afford spiro[1,3]oxazino[2,3-a]isoquinoline derivatives in high yields.     

Three-component condensation of 4-aryl-1,4-dihydro-benzo[4,5]imidazo[1,2-<Emphasis Type="Italic">a</Emphasis>][1,3,5]triazin-2-amines with formaldehyde and primary amines

Three-component cyclization of 4-aryl-1,4-dihydrobenzo[4,5]imidazo[1,2-a][1,3,5]triazin-2-amines with formaldehyde and primary amines gave the corresponding 6-unsubstituted or 6-aryl-2-alkyl-2,3,4,6-tetrahydro-1H-[1,3,5]triazino[1′,2′:3,4][1,3,5]triazino[1,2-a]benzimidazoles.     

Cyclization reactions of 1,3-dibromopropan-2-ol, 2,3-dibromopropan-1-ol and 1-bromomethyloxirane with 6-amino-2,3-dihydro-2-thioxo-4(1H)-pyrimidinone

The cyclization reactions, carried out in strongly- or weakly-basic media, are described. Sometimes, 7-amino-2,3-dihydro-3-hydroxymethyl-5H-thiazolo[3,2-a]pyrimidin-5-one is separated out, together with 8-amino-3,4-dihydro-3-hydroxy-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-one, as the principal product. A mechanism of reaction, during which the cyclizating agents are changed into oxirane derivatives, is proposed. The results of single-crystal X-ray investigations on 8-amino-3,4-dihydro-3-hydroxy-7-nitroso-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-one (R = 0.035 for 1013 reflections), and on 7-hydroxymethyl-6,7-dihydrothiazolo[3,2-a][1,2,3]triazolo[4,5-d]pyrimidin-9(1H)-one (R = 0.027 for 1607 reflections) are reported.     

Synthesis of 1,3,4-thiadiazolo[3′,2′∶1,2]pyrimidino[5,6-d]-1,3-thiazine derivatives

2-R-5-Imino-6H-1,3,4-thiadiazolo[3,2-a]pyrimidin-7-ones react with aromatic and heterocyclic aldehydes in the presence of Et₃N to give condensation products on the methylene group, which react with carbon disulfide to yield the corresponding 2,6-disubstituted 8-thioxo-9,9a-dihydro-1,3,4-thiadiazolo[3′,2′∶1,2]pyrimidino[5,6-d]1,3-thiazin-5-ones. Deceased. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 366–368, February, 1999.     

The [4+2]-cycloaddition of ketene containing both acyl and imidoyl groups to aldehyde: Synthesis,crystal and molecular structure of 1-p-bromophenyl-4-p-toluoyl-1, 3-dihydro-5H-[1,3]oxazino[4,3-c][1,4]benzoxazine-3,5-dione

Thermal decarboxylation of 3-p-toluoyl-1,2-dihydro-4H-pyrrolo[5,1-c][1,4]benzoxazine-1, 2,4-trione resulted in 2-oxo-2H-1,4-benzoxazin-3-yl(p-toluoyl)ketene; the latter under-goes [4+2]-cycloaddition withp-bromobenzaldehyde to form 1-p-bromophenyl-4-p-toluoyl-1, 3-dihydro-5H-[1,3]oxazino[4,3-c][1,4] benzoxazine-3,5-dione. The crystal and molecular structure of the latter has been studied by X-ray analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1633–1636, September, 1993.     

Synthesis and Transformations of 5-Substituted 2-Aryl-7H-[1,2,4]triazolo[3,2-b][1,3]thiazin-7-ones and 2-Aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones

3-Aryl-1,2,4-triazole-5-thiones react with dimethyl acetylenedicarboxylate and methyl 3-phenyl-propynoate to afford the corresponding 5-substituted 2-aryl-7H-[1,2,4]triazolo[3,2-b][1,3]thiazin-7-ones. Treatment of 2-aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones with alkalies leads to formation of 3-(benzimidazol-2-ylsulfanyl)-3-arylpropionic acids, their reaction with methyl p-toluenesulfonate yields 1-(3-methyl-2-thioxo-2,3-dihydro-1N-benzimidazol-1-yl)-3-phenyl-2-propen-1-one, and oxidation with hydrogen peroxide gives benzimidazole-2-sulfonic acid and 3-aryl-2-propenoic acids.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 109–114.Original Russian Text Copyright © 2005 by Britsun, Esipenko, Chernega, Lozinskii.     

Acylimines of hexafluoroacetone and methyl trifluoropyruvate in cyclocondensation with 2-aminothiazolines

Reactions of acylimines of hexafluoroacetone and methyl trifluoropyruvate with 2-aminothiazolines afforded fluorine-containing heterocycles of two structural types: 6,7-dihydro-2H-thiazolo[3,2-a][1,3,5]triazines and 2,3,5,6-tetrahydroimidazo[2,1-b]thiazoles. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1619–1622, July, 2005.     

Novel heterocyclic systems based on 8-R-4,5-dihydro-4,4-dimethyl-[1,2]dithiolo[3,4-c]quinoline-1-thiones

Based on the reaction of 8-R-4,5-dihydro-4,4-dimethyl[1,2]dithiolo[3,4-c]quinoline-1-thiones with oxalyl chloride followed by the reactions of 1,3-dipolar cycloaddition and diene synthesis with participation of acetylenedicarboxylic acid dimethyl ester, we have developed approaches to synthesis of novel polycondensed heterocyclic systems: [1,2]dithiolo[3,4-c]pyrrolo[3,2,1-ij]quinoline-4,5-dione, 6-(1,3-dithiol-2-ylidene)-1,2-dioxo-5-thioxo-7H-pyrrolo[3,2,1-ij]quinoline and 4,5-dioxospiro(pyrrolo)-[3,2,1-ij]thiopyrano[2,3-c]quinoline-11,2′-[1,3]dithiole. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 610–615, April, 2006.     

Cyclization of Nitrospirobenzopyrans to Bridged Benzoxazepino[3,2-a]indoles

Summary. Condensation of 1-substituted 1,2,3,9a-tetrahydro-9H-imidazo[1,2-a]indol-2-ones with 5-nitrosalicylaldehyde afforded 1′-[(N-monosubstituted carbamoyl)methyl]indoline nitrospirobenzopyrans. Treatment of the latter with strong base led to the formation of a mixture of cis/trans-5a,13-methano-1,3-benzoxazepino[3,2-a]indoles. Results of semiempirical calculations gave evidence that such a transformation of nitrospirobenzopyrans to bicyclic indole derivatives could proceed via a single transition state, where the negatively charged carbon atom attacks the vinylic double bond of the spiropyran system.     

Reaction of methyl 1-bromocyclopentane- and 1-bromocyclohexanecarboxylates with zinc and 2-arylmethylidene-2,3-dihydro-1<Emphasis Type="Italic">H</Emphasis>-inden-1-ones or 2-arylmethylidene-3,4-dihydronaphthalen-1(2<Emphasis Type="Italic">H</Emphasis>)-ones

Methyl 1-bromocyclopentanecarboxylate and methyl 1-bromocyclohexanecarboxylate reacted with zinc and 2-arylmethylidene-2,3-dihydro-1H-inden-1-ones or 2-arylmethylidene-3,4-dihydronaphthalen-1(2H)-ones to give 4′-aryl-4′,5′-dihydro-2′H-spiro[cyclopentane(cyclohexane)-1,3′-indeno[1,2-b]pyran]-2′-ones or 4-aryl-5,6-dihydrospiro[benzo[h]chromene-3,1′-cyclopentane(cyclohexane)]-2(4H)-ones, respectively.