Claims
- 1. A method of preparing a compound of the formula: ##STR12## wherein R.sub.3 " and R.sub.4 " are selected from the group consisting of hydrogen, (C.sub.1 -C.sub.6)alkyl or hydroxy; R.sub.5 and R.sub.6 are hydrogen; R.sub.1 and R.sub.2 are each (C.sub.1 -C.sub.6)alkyl or R.sub.1 is (C.sub.1 -C.sub.6)alkyl and R.sub.2 is --(CH.sub.2).sub.n --R.sub.17, where n=2-6 and R.sub.17 is selected from the group consisting of hydroxy, trialkylsilyloxy or R.sub.1 and R.sub.2 taken together with their associated N(itrogen) are selected from the group consisting of pyrrolidine, piperidine or moieties of the formula: ##STR13## wherein R.sub.7 and R.sub.8 are independently selected from (C.sub.1 -C.sub.6)alkoxy, trialkylsilyloxy or hydrogen; R.sub.9 and R.sub.10 are independently selected from hydrogen, hydroxymethyl or trialkylsilyloxymethyl with the proviso that only one of R.sub.7, R.sub.8, R.sub.9 and R.sub.10 can be one of the above disclosed substituents other than hydrogen; which comprises successively reacting a compound of general formula: ##STR14## wherein P is (C.sub.1 -C.sub.6)lower alkyl, arylmethyl or substituted cyclohexyl or substituted oxazalone; with ozone followed by zinc in acetic acid or a phosphine such as triphenylphosphine or a thioether such dimethylsulfide; then reacting the above product with a compound of formula: ##STR15## wherein R'.sub.1 and R'.sub.2 are each (C.sub.1 -C.sub.6)alkyl or R'.sub.1 is (C.sub.1 -C.sub.6)alkyl and R'.sub.2 is --(CH.sub.2).sub.n --R.sub.17, where n=2-6 and R.sub.17 is selected from the group consisting of hydroxy, trialkylsilyloxy or R'.sub.1 and R'.sub.2 taken together with their associated N(itrogen) are selected from the group consisting of pyrrolidine, piperidine or moieties of the formula: ##STR16## wherein R.sub.7 and R.sub.8 are independently selected from the group consisting of (C.sub.1 -C.sub.6)alkoxy, trialkylsilyloxy or hydrogen; and R.sub.9 and R.sub.10 are independently selected from hydrogen, hydroxymethyl, or trialkylsilyloxymethyl with the proviso that only one of R.sub.7, R.sub.8, R.sub.9 and R.sub.10 can be one of the above disclosed substituents other than hydrogen; and adding to the reaction mixture sodium cyanoborohydride and concomitant cyclization of the reduced intermediate.
CROSS REFERENCE TO RELATED APPLICATIONS
This is a divisional of application Ser. No. 07/690,749 filed on Apr. 24, 1991 now U.S. Pat. No. 5,356,885.
US Referenced Citations (4)
Divisions (1)
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Number |
Date |
Country |
Parent |
690749 |
Apr 1991 |
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