Synthesis of 5-Oxo and 7-Oxopyrido[2,3-d]pyrimidines

The synthesis of 4-amino-2-methylthio-5-oxopyrido[2,3-d]pyrimidine 4 and its isomer, 4-amino-2-methyl-thio-7-oxopyrido[2,3-d]pyrimidine 6 is described. The regiochemistry of the reaction of 4,6-diamino-2-methyl-thiopyrimidine 9 and diethyl ethoxymethylene malonate 12 is discussed.     

Synthesis of 1-phenyi-1H-tetrazolo[4,5-d]tetrazole and 5-aryl-1-(4-bromophenyl)-1,2,4-triazolo[4,3-d]tetrazoles

l-Phenyl-lH-tetrazol-5-yIhydrazine (2) was reacted with nitrous acid to yield 1-phenyl-lH-tetrazolo[4,5-d]tetrazole (3). l-Arylidene-2-(l-phenyl-lH-tetrazol-5-yl)hydrazines (4) were generally reactive towards electrophilic reagents. When treated with bromine in acetic acid, 4 yielded mixtures of 1-arylidene-2-[1-(4-bromophenyl)-lH-tetrazol-5-yl]hydrazines (5a-d) and 2-[1-(4-bromophenyl)-lH-tetrazol-5-yl]hydrazidic bromides (6a-d). Solvolysis of 6a-d in aqueous acetone yielded 5-aryl-1-(4-bromophenyl)-1,2,4-triazolo[4,3-d]tetrazoles (7a-d). The structures of the synthesized compounds were confirmed on the basis of elemental analysis, IR and ¹H NMR data.     

Synthesis and cytotoxicity studies of novel [1,2,4]triazolo[1,5-a]pyrimidine-7-amines

A series of novel N-anilino-5-methyl-2-(3-(5-(alkylaminomethyl)furan-2-yl-methylthio)propyl)-[1,2,4]triazolo-[1,5-a]pyrimidine-7-amine derivatives were synthesized and evaluated for their in vitro cytotoxicity against two cancer cell lines, Bel-7402 and HT-1080. Compounds 9, 14, 19 and 23 possessed marked cytotoxicity, especially 23 (with IC(50) values of 15.0 microM and 7.8 microM against Bel-7402 and HT-1080 cell lines, respectively), which had emerged as lead compound. The activity was found to depend strongly on substitution pattern of the side chains at C-2 position, and 4-triflouromethylanilino substituent at C-7 position was an option for anticancer potency.     

Synthesis of 7-alkyl-2,4-dimethoxy-5-oxo-5H-pyrano[4,3-d]pyrimidines

A convenient synthesis of 7-alkyl-2,4-dimethoxy-5-oxo-5H-pyrano[4,3-d]pyrimidines from methyl 2,4-dimethoxy-6-phenylselenylmethyl (or 6-phenylthiomethyl)-5-pyrimidinecarboxylate with alkylaldehydes is described.     

Synthesis of 2-mercaptothieno[3,2-d]- and 2-mercaptobenzo[4, 5]thieno[2,3-d]thiazoles

2-Mercaptothieno[3,2-d]- and 2-mercaptobenzo[4, 5]thieno[2,3-d]thiazoles were synthesized by reduction of bis(3,3′-nitro-2,2′-thienyl) and bis(2,2′-nitrobenzo[b]thien-3,3′-yl) disulfides, respectively, with sodium hydrosulfite or sodium sulfide in the presence of carbon disulfide.     

Synthesis and in vitro cytotoxicity studies of novel triazolo[4,3-b]pyridazinones

New triazolo[4,3-b]pyridazinones were synthesized and evaluated for their potential in vitro cytotoxic antitumor properties. The compounds were prepared by 1,3-dipolar cycloaddition of pyridazin-3-ones with N-aryl-C-ethoxycarbonylnitrile imines, generated in situ from ethylhydrazono-á-bromoglyoxylates. The peri- and regioselectivity of the reaction were ascertained by ¹H and ¹³C NMR spectroscopy of the cycloadducts.     

4-氯-7H-吡咯并[2,3-d]嘧啶与2,4-二氯-7H-吡咯并[2,3-d]嘧啶的合成研究

报道了以廉价易得的丙二酸二乙酯为起始原料,经过α-烷基化、环合、氯化、烯键氧化和SNAr/环化五步反应,高收率地得到目标产物4-氯-7H-吡咯并[2,3-d]嘧啶(6)和2,4-二氯-7H-吡咯并[2,3-d]嘧啶(10)(总收率分别达到45.8%和44.8%)的合成方法,并对中间体和产物的化学结构进行了表征.     

Synthesis of 5H-Tetrazolo[1,5-d] [1,4]benzodiazepin-6(7H)ones

Syntheses of 5H-tetrazolo [1,5-d] [1,4 ]benzodiazepin-6(7H)ones 2a-d from 5-(o-aminophenyl)-tetrazoles 1a-d and bromoacetyl bromide are described. Compounds 2a-d are representatives of a novel tricyclic ring system. Several alternate methods for the synthesis of 2a-d were attempted without success. Spectral evidence for structural assignments 2a-d is presented. Chemical evidence for these assignments includes the transformation of 2a to 6-(2,2-dimethylhydrazino)-5H-tetrazolo[1,5-d] [1,4]benzodiazepine ( 19 ) via the thione analog of 2a ( 18 ).     

Synthesis of 5H-Triazolo[1,5-d]- and 5H- Tetrazolo- [1,5-d]thieno[3,2-f]-1,4-diazepin-6(7H)-ones

5H-Triazolo[1,5-d]- and 5H-tetrazolo[1,5-d]thieno[3,2-f]-1,4-diazepin-6(7H)-ones have been obtained by the base catalysed ring expansion reaction of 5-chloromethyl-1,2,4-triazolo[1,5-c]- and 5-chloromethyltetrazolo- [1,5-c]thieno[3,2-e]pyrimidines. The required thienopyrimidine derivatives were synthesized from 2-amino-3-triazolyl- and 2-amino-3-tetrazolylthiophenes by acylation, followed by dehydrative cyclization.     

Synthesis of 1-arylacenaphtho[1,2-d]pyrazoles and 5,7-Dehydro-5H,7H-benzo[b]acenaphtho[1,2-e]-1,3a,6a-triazapentalenes

2-Benzoyl- 5 and 2-acetylacenaphthenone 6 , prepared from the corresponding 1-acyl-2-(1-pyrrolidinyl)-acenaphthylenes 2 and 3 , reacted with arylhydrazines 8 under acidic conditions to give the corresponding 1-arylacenaphtho[1,2-d]pyrazoles 9 and 10 . Novel heteropentalene mesomeric betaines, 5,7-dehydro-5H,7H-benzo[b]acenaphtho[1,2-e]-1,3a,6a-triazapentalenes 13 and 14 were prepared by reductive cyclization of 1-(o-nitrophenyl)acenaphtho[1,2-d]pyrazoles 9d and 10d , respectively.     

Synthesis of imidazo[5,4-d] [1,3]thiazines: X-ray structure of N-methyl-N′-[5-(methylamino)-3-nonylimidazo[5,4-d] [1,3]thiazin-7(3H)-ylidene]thiourea

N-Alkyl-N′-[5-(alkylamino)-3-alkylimidazo[5,4-d] [1,3]thiazin-7(3H)-ylidene]thioureas were obtained by the reaction of 1-substituted 5-amino-4-cyanoimidazoles with alkyl isothiocyanates. The structure of this heterocyclic system was confirmed by single crystal X-ray diffraction analysis.     

Synthesis of 2-Methylbenzanthreno[2,3-d]imidazol-7-one

The synthesis of the benzanthrone based heterocyclic compound 2-methylbenzanthreno[2,3-d]imidazol-7-one has been achieved. It shows a strong luminescence intensity in the yellow-green region of the spectrum.     

New Synthesis of Pyrido[2,3-d] and [3,2-d]Oxazines

N-Hydroxyquinolinimide 1 reacts with each of aromatic amines, hydrazine hydrate and aromatic hydrocarbons to give arylcarbamoyl pyridines 2, pyrrolopyridines 3, pyridopyridazines 4 and pyridooxazinones 5 and 6. The heterocycles 5 and 6 can be transformed to the condensed systems, triazolopyridopyridazines 14 and 15 through series of reactions.     

Synthesis of bifunctional thieno[3,2-c]pyrazole,pyrazolothieno[2,3-d]pyrimidin derivatives and their antimicrobial activities

A simple and convenient route was performed for the synthesis of some new heterocyclic compounds based on thieno[3,2-c]pyrazole derivative for antimicrobial evaluation. The key intermediate, 5-amino-3-methyl-1-phenyl-1H-thieno[3,2-c]pyrazole-6-carbohydrazide 3, was prepared by Gewald’s synthesis of Ethyl 5-amino-3-methyl-1-phenyl-1H-thieno[3,2-c]pyrazole-6-carboxylate 2. This intermediate reacted with various reagents to afford different fused and polyfunctional substituted. The structures of these compounds were confirmed by elemental analysis, IR, ¹H NMR, ¹³C NMR and mass spectral data. All the new synthesized compounds were screened for various microorganisms such as Aspergillus fumigatus; Geotrichum candidum; Syncephalastrum racemosum (Fungus); Candida albicans (Yeast fungus); Staphylococcus aureus; Bacillus subtilis (as Gram-positive bacteria); Pseudomonas aeruginosa and Escherichia coli (as Gram-negative bacteria) by the disc diffusion method. In general, the novel synthesized compounds possessed moderate to high antimicrobial activity against the previously mentioned microorganisms.     

Synthesis and X-ray diffraction and calorimetric studies of LaLiMnFeO5 and LaCsMnFeO5 ferrites

Ferrites LaLiMnFeO₅ and LaCsMnFeO₅ were synthesized for the first time by ceramic technology from mixtures of lanthanum(III), manganese, and iron(III) oxides with lithium or cesium carbonate. The compounds were shown by X-ray diffraction to crystallize in the orthorhombic system; the unit cell parameters were determined. The heat capacities were found experimentally for 298.15–673 K. Equations for the heat capacities as a function of temperature were derived and used to calculate the thermodynamic functions C _p ⁰ (T), S ⁰(T), H ⁰(T)?H ⁰(298.15), and Φ**(T) for the above temperature range.     

Condensed thiazoles,II: Synthesis of 7-substituted thiazolo[4,5-d]pyrimidines as possible anti-HIV,anticancer, and antimicrobial agents

Summary Some 3-substituted 2-thioxothiazolo[4,5-d]pyrimidin-7(6H)-ones (2a,b;4) have been synthesized and converted to their 7-chloro (3,5), 7-diethanolamino (6a,b), 7-bis(2-chloroethyl)amino (7), 7-azido (8), 7-amino (9), 7-hydrazino (16), 7-mercapto (11a,b), and 7-methylthio (12) derivatives. These compounds were evaluated for theirin vitro antimicrobial, anti-HIV; and anticancer activities.For part I of this series, see Monatsh Chem127: 1203