| abstract |
Cpds.: are easily aceesible by reducing cpds. (II) or (III) with excess Na-borohyhdride in polar organic solvents at 40-100 degrees: (where R1, R2, R3 and R4 are opt. same but R1, R2 pref. differ from R3, R4 and = is not >6C alkyl or opt. substd. cycloalkyl; R1-R2 and/or R3-R4 being opt. linked by 2-4C alkylene opt. interrupted by O or S or N, the latter opt. carrying alkyl, aralkyl or aryl, or R1 and/or R2 = H or an opt. substd. aromatic or heterocyclic residue (R1 pref. = thiazole, benzthiazole, pyridine, pyrimidine, pyridazine, uracil or thiophene, or R1R2N pref. = (Y=CH2CH2, CH=CH, OCH2, SCH2, -N(alk)CH2 or N=CH) or R1+R2 = two Ph ortho-linked by CH2CH2, CH=CH, OCH2, SCH2, N(alk)CH2 or N=CH; R5 = H, 6C alkyl or opt. substd. aryl; X is an equivalent of a strong acid). |