Abstract: Disclosed is a compound of formula 1, or a pharmaceutically acceptable salt thereof, where R1, R2, R3, R4, R5, R6, R7, R7?, R8, R9, R10, R11, R12 and R13 are as disclosed herein. Also, disclosed is a process for the preparation of the compound of formula 1, or a pharmaceutically acceptable salt thereof, and intermediates used therein. The compound of formula 1 can be used in the preparation of halichondrin analogs, such as Eribulin; and a process for its preparation from the compound of formula 1 is also disclosed.

Abstract: Disclosed is a compound of formula 1, or a pharmaceutically acceptable salt thereof, where R1, R2, R3, R4, R5, R6, R7, R7?, R8, R9, R10 , R11 , R12 and R13 are as disclosed herein. Also, disclosed is a process for the preparation of the compound of formula 1, or a pharmaceutically acceptable salt thereof, and intermediates used therein. The compound of formula 1 can be used in the preparation of halichondrin analogs, such as Eribulin; and a process for its preparation from the compound of formula 1 is also disclosed.

Abstract: Disclosed is a compound of formula 1, or a pharmaceutically acceptable salt thereof, where R1, R2, R3, R4, R5, R6, R7, R7?, R8, R9, R10, R11, R12 and R13 are as disclosed herein. Also, disclosed is a process for the preparation of the compound of formula 1, or a pharmaceutically acceptable salt thereof, and intermediates used therein. The compound of formula 1 can be used in the preparation of halichondrin analogs, such as Eribulin; and a process for its preparation from the compound of formula 1 is also disclosed.

Abstract: Disclosed is a compound of formula 1, or a pharmaceutically acceptable salt thereof, where R1, R2, R3, R4, R5, R6, R7, R7?, R8, R9, R10, R11, R12 and R13 are as disclosed herein. Also, disclosed is a process for the preparation of the compound of formula 1, or a pharmaceutically acceptable salt thereof, and intermediates used therein. The compound of formula 1 can be used in the preparation of halichondrin analogs, such as Eribulin; and a process for its preparation from the compound of formula 1 is also disclosed.

Abstract: Treprostinil is prepared by a process which involves Pauson-Khan cyclization of an an alkene-substituted, alkyne-substituted benzene corresponding to formula: (I) where PMB represents para-methoxy benzyl protecting group and R1 and R2 are alcohol protecting groups. Following cyclization, the resulting compound can be subjected to several chemical trans-formations followed by alkylation, hydrolysis and salt formation to yield treprostinil sodium. The use of para-methoxybenzyl group as the phenolic protecting group confers several process advantages that result in simplified purification of the final product and improved yields.

Abstract: Cisapride, i.e. cis-4-amino-5-chloro-N-?1-?3-(4 fluoro-phenoxy)propyl!-3-methoxy-4-piperidinyl!-2-methoxy-benzamide, and similar benzamide derivatives, are prepared from novel 1-aryloxyalkyl- or 1-aralkyl-3-arylcarbonyloxy-4-oxo-piperidines, by nuclear substituent re arrangement involving acyl transfer under animal forming conditions, to give the corresponding 1-aryloxyalkyl- or 1-aralkyl-3-hydroxy-4-lower alkoxy-4-arylamido piperidine. This in turn is readily converted to the corresponding 3-oxo-4-arylamido-piperidine by reaction with strong organic acid, which can then be reduced, deprotected and 3-methylated to give the final compound, e.g. cisapride.

Abstract: Cisapride, i.e. cis-4-amino-5-chloro-N-[1-[3-(4 fluoro-phenoxy)propyl]-3-methoxy-4-piperidinyl]-2-methoxy-benzamide, and similar benzamide derivatives, are prepared from novel 1-aryloxyalkyl- or 1-aralkyl-3-arylcarbonyloxy-4-oxo-piperidines, by nuclear substituent re arrangement involving acyl transfer under animal forming conditions, to give the corresponding 1-aryloxyalkyl- or 1-aralkyl-3-hydroxy-4-lower alkoxy-4-arylamido piperidine. This in turn is readily converted to the corresponding 3-oxo-4-arylamido-piperidine by reaction with strong organic acid, which can then be reduced, deprotected and 3-methylated to give the final compound, e.g. cisapride.

Abstract: Cisapride, i.e. cis-4-amino-5-chloro-N-[1-[3-(4 fluoro-phenoxy)propyl]-3-methoxy-4-piperidinyl]-2-methoxy-benzamide, and similar benzamide derivatives, are prepared from novel 1-aryloxyalkyl- or 1-aralkyl-3-arylcarbonyloxy-4-oxo-piperidines, by nuclear substituent re arrangement involving acyl transfer under animal forming conditions, to give the corresponding 1-aryloxyalkyl- or 1-aralkyl-3-hydroxy-4-lower alkoxy-4-arylamido piperidine. This in turn is readily converted to the corresponding 3-oxo-4-arylamido-piperidine by reaction with strong organic acid, which can then be reduced, deprotected and 3-methylated to give the final compound, e.g. cisapride.

Abstract: Pure Form 1 ranitidine hydrochloride is prepared by a process of crystallization from a solution of ranitidine hydrochloride in a mixed solvent comprising 1 part by volume of at least one lower alkanol such as ethanol and 1-2.0 parts by volume of a C.sub.6 -C.sub.10 aromatic hydrocarbon such as toluene, and in the presence of seed crystals of pure Form 1 ranitidine hydrochloride. In the preferred process according to the invention, the ranitidine hydrochloride is prepared in situ in the solvent mixture by adding hydrochloric acid to a solution of the free base in the solvent mixture, in the presence of the seed crystals.