2- Methyl-4 thieno pyrimidine

Thieno[2,3-d ]pyrimidin-4(3 H) -one, 3-methyl-synthesis, 4, 1017 Thieno[2,3-d ]pyrimidin-4-ones synthesis, 4, 1017, 1018, 1022 Thieno[2,3-6]pyrrole, 5-aryl-synthesis, 6, 1009 Thieno[2,3-6]pyrrole, N-benzyl- H NMR, 4, 1042 UV spectra, 4, 1044 Thieno[2,3-c]pyrrole, N-ethyl-UV spectra, 4, 1044 Thieno[3,2-6]pyrrole, 5-aryl-synthesis, 6, 1009 Thieno[3,2-6]pyrrole, N-benzyl- H NMR, 4, 1041, 1042 lithiation, 4, 1051 UV spectra, 4, 1044 Thieno[3,2-6]pyrrole, 2,3-dihydro-desulfurization, 6, 984 oxidation, 6, 981... 

The thieno[3,2-d]pyrimidine-2,4-diones were prepared as shown in Scheme 237, and their silyl derivatives were coupled with various acetoxy-methyl ethers in the presence of stannic chloride to give diseco (type 2.1), triseco (type 3.1), and pentaseco benzyl derivatives of type 5.1 nucleosides (94JHC305). 

Nielsen (81CS(18)135) prepared thieno[2,3-4]pyrimidin-4(3//)-ones in 43-90% yield by heating 2-acylaminothiophene-3-carboxylates (330) with phosphorus pentoxide, N,N -dimethylcyclohexylamine and an amine hydrochloride at 180 °C. By raising the temperature to 240 °C, thieno[2,3-4]pyrimidin-4-amines (331) were obtained in 27-34% yield (Scheme 92). Phenyl N,N -dimethylphosphorodiamidate [(MeNH)2P(0)OPh], a well-known reagent for the synthesis of 3-methyl-4-oxo-3,4-dihydroquinazolines (77S180), reacts with thiophene derivatives of type (330) to give 3-methylthieno[2,3-4]pyrimidin-4(3/f)-ones (78ACS(B)303). 

Electrophilic substitution reactions of thieno[3,2-cf pyridine occur at position 7 (equation 38). With dimethyl sulfate in an alkaline medium, thieno[3,2-cf pyrimidin-4-one (347) yields an N-methyl derivative. 

Strong heating of 2-substituted 5-propargylsulfanyl-3-aryl-3//-pyrimidin-4-ones, and their 5-allylsulfanyl derivatives, has been shown to lead to 2-substituted 3-aryl-6-methyl-3//-thieno[3,2-d]pyrimidin-4-ones and their 6,7-dihydro derivatives. The proposed mechanism in both cases is a [3,3]-sigmatropic thia-Claisen rearrangement followed by tautomerization and a 5-exodig or 5-exo-trig cyclization.38... 

The reaction between carboxamide 31 [R2 = R3 = (CH2)4] and 3,3-bismethylthio-2-cyanoacrylonitrile 34a in refluxing DMF containing sodium carbonate, gave 2-cyano-2-(thieno[2,3-d]pyrimidin-2-ylidene)acetonitrile 35 in 69% yield. Under the same reaction conditions, each carboxamide 31 [R2 = R3 = Me or (CH2)4] reacted with methyl 3,3-bismethylthio-2-cyanoacrylate 34b and gave good yields of 2-cyano-2-(thieno[2,3-d]-pyrimidin-2-ylidene)acetates 35b and 35c, respectively (87GEP249020). 

The reaction of 2-oxo-4-thioxopyrimidin-5-carbonitrile 117 with methyl chloroacetate in the presence of methanolic sodium ethoxide gave thieno[2,3-d]pyrimidine 118 [84JCS(P1)2447]. 2,4-Dithioxopyrimidine-5-carbonitrile 119 was reacted with acetonitrile or various a-chlorocarbonyl compounds in ethanol containing sodium acetate to give the corresponding thieno[2,3-d]pyrimidines 120 (91PS223). 

To synthesize 2-methyl-3-substituted thienopyrimidin-4-ones 178, a two-step reaction was applied. o-Aminoesters 189 (Y = Me) were reacted with acetic anhydride in the presence of 4-dimethylaminopyridine to give methyl 3-acetylaminothiophene-2-carboxylates 196. These were then cyclized by heating with primary amines to the thieno[3,2-d]pyrimidin-4-ones 197 (91GEP295381 92PHA577). 

Thieno[3,2-d]pyrimidine-2(l//)-thiones 217-219 and -4(3//-thiones 245 were S-methylated smoothly with methyl iodide in base to the corresponding 2-methylthio (82EUP43054 89CPB1197) and 4-methylthio (86JHC 1757) compounds. 5-Alkylation of thieno[3,2-d]pyrimidin-4(3//)-one-2(l//)-thione 223 with alkyl halides in dilute sodium hydroxide solution afforded 2-alkylthio derivatives 284. Nucleophilic displacement of the alkyl-thio group in compound 284 by primary amines has also been reported (90EUP404356). 

Treatment of o-aminoesters 338 with thiophosgene in chloroform afforded isothiocyanates 339, which were either refluxed with 2-methyl-allylamine in dichloromethane to afford 3-(2-methyl-2-propenyl)thieno-[3,4-d]pyrimidin-4-ones 340, or treated with ethanolamine to yield the 3-(2-hydroxyethyl) derivatives 341. Derivatives 340 were obtained directly from o-aminoesters 338 by heating with allylisothiocyanate in propan-1-ol (89CPB2122). 

Heating compound 299 with phosphorus pentasulfide in a mixture of dioxane and pyridine gave 7-(2,3,5-tri-0-benzoyI-/3-D-ribofuranosyl) thieno[3,4-d]pyrimidin-4(3//)-thione 374, in 49% yield. Thione 375, obtained by debenzoylating compound 374, was converted into the 4-methyl-thio-7-/3-D-ribofuranosylthieno[3,4-d]pyrimidine 376 by reaction with excess methyl iodide in 0.1 N aqueous sodium hydroxide. Substitution of the... 

Thieno[3,4-d]pyrimidines with a 4-(4-fluorobenzoyl)piperidine or bis(4-fluorophenyl)methyl-4-piperylidene substituent instead of the 4-phenyl-substituted piperazine group in compounds 306 were twenty times more potent as selective 5-HT2 antagonists than ketanserin (91MI1). 

Preparation of 3-methyl-l-(2-methylpropyl)-6-(l-naphthalenylmethyl) thieno[2,3-d]-pyrimidine-2,4(lH,3H)-dione... 

In the antiinfective field, the synthesis and evaluation of pyrimidinone antibiotics with a broader spectrum against Gram-positive bacteria was reported <03BMCL2641>. New pyrimidines <03IJC910, 031JH217>, pyrimidine-incorporated 1,3,4-thiadiazoles <031JH245>, pyrazolo[3,4-ci]pyrimidines <03HAC530>, N-[5-(2-furanyl)-2-methyl-4-oxo-4//-thieno[2,3-... 

Thieno[2.3-d]-pyrimidin 2-Chlor-4-hydrazino-3-methyl- E16a, 737 (Cl -v NH-NH2)... 

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