title: Synthesis of functionalized tetrahydro-1,3-diazepin-2-ones and 1-carbamoyl-1H-pyrroles via ring expansion and ring expansion/ring contraction of tetrahydropyrimidines.
abstract: A general approach to 6-phenylthio-substituted 2,3,4,5-tetrahydro-1H-1,3-diazepin-2-ones based on the ring expansion reaction of 1,2,3,4-tetrahydropyrimidin-2-ones under the action of nucleophiles has been developed. The first step of the synthesis was preparation of N-[(2-benzoyloxy-1-tosyl)ethyl]urea by three-component condensation of 2-benzoyloxyethanal, urea and p-toluenesulfinic acid. Nucleophilic substitution of the tosyl group in the obtained sulfone with sodium enolates of α-phenylthioketones followed by cyclization-dehydration, and debenzoylation gave 4-hydroxymethyl-5-phenylthio-1,2,3,4-tetrahydropyrimidin-2-ones which were transformed into the 4-mesyloxymethyl-derivatives. Treatment of the latter with nucleophilic reagents, such as NaCN, sodium diethyl malonate, PhSNa, MeONa, NaBH(4), sodium succinimide, or potassium phthalimide, afforded the target multi-functionalized diazepinones. The obtained 6-phenylthio-diazepinones and their 6-tosyl-substituted analogues were converted into 3-substituted 1-carbamoyl-1H-pyrroles under acidic conditions as a result of ring contraction. Effective one-pot synthesis of the latter from 4-mesyloxymethyl-pyrimidines was realized using a ring expansion/ring contraction sequence.
authors.affiliation: Department of Organic Chemistry, Moscow State Academy of Fine Chemical Technology, 86 Vernadsky Avenue, 119571, Moscow, Russian Federation.
authors.forename: Anastasia A
authors.initials: AA
authors.lastname: Fesenko
authors.forename: Ludmila A
authors.initials: LA
authors.lastname: Trafimova
authors.forename: Anatoly D
authors.initials: AD
authors.lastname: Shutalev
mesh_terms: D001381:Azepines / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D011743:Pyrimidines / Q000737:chemistry*; D011758:Pyrroles / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D001381:Azepines; D011743:Pyrimidines; D011758:Pyrroles