576-28-3

Upstream product

• 104369-27-9 3-methyl-2-thioxo-2,3,r-4a,c-5,c-8,c-8a-hexahydro-5,8-methanoquinazolin-4(1H)-one 
• 104369-27-9 3-methyl-2-thioxo-2,3,r-4a,t-5,t-8,c-8a-hexahydro-5,8-methanoquinazolin-4(1H)-one 
• 104308-57-8 (1R,2R,3S,4S)-3-(3-Methyl-thioureido)-bicyclo[2.2.1]hept-5-ene-2-carboxylic acid 
• 104308-57-8 (1S,2R,3S,4R)-3-(3-Methyl-thioureido)-bicyclo[2.2.1]hept-5-ene-2-carboxylic acid 
• 6327-98-6 2-methylthio-3-methylpyrimidin-4(3H)-one 

Downstream Products

• 6104-45-6 3-methylpyrimidin-4-one 
• 608-34-4 3-methyluracil 

Relevant academic research and scientific papers

New 1,3-diazadienes used in heterocyclic synthesis

The synthesis of dihydropyrimidines, dihydropyrimidinones and thiadiazine-1,1-dioxides starting from neutral or cationic 2-methylthio-1,3- diazadienes is described. Addition of H2S followed by loss of methanethiol led to the corresponding thiocarbonyl compounds.

Synthesis and structure of norbornane/ene-fused thiouracils and thiazino[3,2-a]pyrimidinones

Ethyl diexo- 3-aminobicyclo[ 2.2.1]heptane- and -hept-5-ene-2- carboxylares (1a,b) and the diendo derivatives were transformed with thiophosgene to the isothiocyanates (2a,b and 3a, b) and then cyclized to the norbornane/enecondensed 2-thioxopyrimidin-4-ones (4a, b and 5a, b). On heating, the norbornene compounds (4b and 5b) furnished thiouracil (6) via cyelopentadiene elimination. With dimethyl acetylenedicarboxylate, the thioxopyrimidinones (4a,b) and (5a,b) form angularly-fused [1,3]thiazino[3,2- a]pyrimidinones (7a,b and 8a,b). On heating, 7b decomposes to give 3-methyl- 2,3-dihydro-2-thioxo-4(1H)-pyrimidinone (9) in a retro Diels-Alder process by methyl migration and splitting-off of cyclopentadiene. The structures were elucidated by IR and NMR spectroscopies, with DNOE, DEPT and 2D-HSC techniques.

FUSED-SKELETON SATURATED SIX-MEMBERED 1,3-N,O, N,N AND N,S HETEROCYCLES, FUSED-SKELETON ARYL-SUBSTITUTED SATURATED ISOINDOLONES

In the introduction, a brief survey is given of the main types of fused-skeleton saturated six-membered 1,3-heterocycles serving as model compounds in our earlier investigations and as starting compounds in the present studies.The synthesis and conformational analysis of aryl-substituted fused-skeleton saturated 1,3-oxazines and of aryl-substituted hetero-condensed saturated isoindolones are treated. cis-trans isomerization in the saturated isoindolone moiety of the resulting tricyclic, tetracyclic and pentacyclic systems is discussed in connection with the ring-closure reactions of cis- and trans-1,2-disubstituted 1,2- and 1,3-difunctional alicyclic compounds to give alicycle-fused six-membered 1,3-heterocycles.The cycloaddition reactions of dihydro-1,3 and 3,1-oxazines and the conformations of the alicycle-fused tetrahydrooxazine-azetidinone derivatives obtained are presented.Methods are given for the preparation of saturated thiazolo- and thiazinoquinazolinones.Unambiguous, mainly one-pot syntheses for the preparation of 1,3-heterocycles by a retro Diels-Alder method are discussed.

Stereochemical Studies. Part 86. Saturated Heterocycles. Part 81. Preparation of New Thiouracils via Retrodiene Decomposition of Methylene-bridged Quinazolone Thiones

endo- and exo-Norbornene (1) and (3) and norbornane (2) and (4) amino acids and isothiocyanates give methylene-bridged 2-thioxohexahydro- (10) and (11) and octahydro- (12) and (13)-quinazolin-4-ones.Compounds (10) and (11) decompose in a reto-Diels-Alder