Formation of Benzo[e]cycloalk[g][1,4]oxazocinones by Reaction of N-Mesyl- or N-Tosyl-N-2-[(1-cycloalken-1-yl)phenyl]glycines with Molecular Bromine

Halolactonization of N-Acyl-N-(2-cyclohex-1-en-1-yl-6-methylphenyl)glycines: Towards Production of 4,1-Benzoxazoheterocycles

“…In the case of aryl-or alkylsulfonylsubstituted analogues, the nature of the hydrocarbon fragment in no way affected the structure of the resulting reaction product. 20,27 In the same study, we found a significant dependence of lactonization directions on the nature of the R substituent in glycines 4a,b. Both N-acyl-substituted glycines have in common that, by the interaction between the acids 4a,b and molecular bromine in the presence of sodium bicarbonate the 7-exo-halogencyclization products 5a,b with the spiro carbon atom are formed (Schemes 3 and 4).…”

“…Since our previous studies have shown that if there is no substituent at this position, then such spatial changes in the structure of the cyclization product cannot be fixed. 20 Using known reactions, the corresponding N-acetyland N-benzoylamides 2a,b were obtained from amine 1. Next, by reacting cyclohexenylanilide 2a or 2b with methyl bromoacetate in the presence of KOH and triethylbenzylammonium bromide (TEBAB) the compounds 3a or 3b were obtained.…”

“…11 The various approaches to the synthesis of the compounds with such backbones make it possible to construct the heterocycles with the required regiolocalization of the nitrogen, oxygen atoms, and functional groups. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] By the interaction of the N-arylsulfonyl (or N-mesyl) glycines I with molecular bromine, we previously obtained the benzoxazocinones II (Scheme 1). 27 Based on generally accepted mechanistic concepts in this field of organic chemistry, it can be assumed that in these halogenation reactions and the subsequent formation of an aryl-fused eight-membered ring several intermediate stages are possible for the conversion of glycine I.…”