Abstract: The present invention relates to a method for preparing di-organo-dialkoxysilanes, in particular di-organo-dialkoxysilanes wherein one or both of the organic substituents are bulky. The method comprises reacting a tetraalkoxysilane compound with a first Grignard reagent to form a mono-organo-tri-alkoxysilane compound, which is then reacted with a chlorinating agent to form a chlorinated mono-organo-di-alkoxysilane which is then reacted with a second Grignard reagent to form the di-organo-di-alkoxysilane compound.

Abstract: The invention relates to a process for preparing (2,3) disubstituted succinates that allows (2,3) disubstituted succinates to be obtained in good purity and with acceptable reaction yields. The (2) and (3) substitutions may be the same or different. The process comprises reacting a haloacetate with a malonic acid ester into a tricarboxylate, which is further reacted to a (2,3) disubstituted tricarboxylate, hydrolyzed, decarboxylated and optionally esterified. Esterified (2,3) disubstituted succinic esters may be used as internal donor in Ziegler-Natta type catalysts for the polymerization of olefins.

Abstract: The invention relates to a process for preparing (2,3) disubstituted succinates that allows (2,3) disubstituted succinates to be obtained in good purity and with acceptable reaction yields. The (2) and (3) substitutions may be the same or different. The process comprises reacting a haloacetate with a malonic acid ester into a tricarboxylate, which is further reacted to a (2,3) disubstituted tricarboxylate, hydrolysed, decarboxylated and optionally esterified. Esterified (2,3) disubstituted succinic esters may be used as internal donor in Ziegler-Natta type catalysts for the polymerisation of olefins.

Abstract: The present invention relates to the process for the preparation of compounds of formula (I) or its pharmaceutically acceptable salts Formula I The novel compounds (i) 10,11-Anhydro-2?,4?-di-O-benzoyl-12-O-imidazolylcarbonyl-6-O-methylerythromycin A of formula (Xa) Formula (Xa) (ii) 2?,4?-di-O-benzoyl-11-amino-11-N-[4-[4-(3-pyridyl)imidazol-1-yl]butyl]-11-deoxy-6-O-methylerythromycin A 11,12-cyclic carbamate of formula (XIa) Formula (XIa) (iii) 2?-O-benzoyl-11-amino-11-N-[4-[4-(3-pyridyl)imidazol-1-yl]butyl]-11-deoxy-5-O-desosaminyl-6-O-methylerythronolide A 11,12-cyclic carbamate of formula (XIIa) Formula (XIIa) (iv) 2?-benzoyl-11-amino-11-N-[4-[4-(3-pyridyl)imidazol-1-yl]butyl]-11-deoxy-5-O-desosaminyl-6-O-methylerythronolide A 11,12-cyclic carbamate of formula (XIIa) Formula (XIIa) and their use as intermediates in formation of compound of Formula I. Also the process of preparation of compound of formula (XIIIa).

Abstract: The present invention relates to novel polymorphs of Telithromycin designated as Form I, II and III and its process for preparation. Also it provides Telithromycin with at least 99% purity.