Abstract: The present invention relates to an efficient process for the preparation of 5-(substituted)-10-methoxy-2,2,4-trimethyl-2,5-dihydro-1H-chromeno[3,4-f]quinolines.

Abstract: In one aspect, the invention relates to a process for preparing 6-O-substituted erythromycin derivatives comprising reacting 2′-substituted and optionally 4″-substituted 9-oxime erythromycin derivatives with an alkylating agent in the presence of a palladium catalyst and phosphine. In another aspect, the invention relates to processes for preparing 6-O-substituted erythromycin ketolides using the palladium-catalyzed alkylation reaction.

Abstract: The claimed invention provides a novel method of preparing 6-O-methyl erythromycin A. The process comprises the steps of reducing the 9-keto group of erythromycin A to form a 9-hydroxy erythromycin A, protecting the 9-, 2'-, and/or 4"-hydroxyl groups of erythromycin A, selectively methylating the 6-position of the 9-hydroxy erythromycin A derivative, deprotecting the hydroxyl groups and oxidizing the 9-hydroxyl to afford 6-O-methyl erythromycin A.

Abstract: The disclosed invention relates to novel 3'-N-O, 9-O-oxime protected, 6-O-alkyl erthyromycin derivatives, a process of preparing the same. The invention also relates to a process of preparing 6-O-alkyl erythromycin A by eliminating the 3'-N-oxide group and 9-O-oxime protecting groups and optionally deprotecting the hydroxy groups at the 2'- and 4"- positions under suitable reaction conditions.

Abstract: A process of preparing 6-O-alkylerythromycin A using 9-oximesilyl erythromycin A derivatives is provided. 9-Oximesilyl- and 6-O-alkylerythromycin A derivatives used in the preparation of 6-O-alkylerythromycin A are also provided.

Abstract: A process of preparing a 6-O-methyl erythromycin A derivative using a 2'-protected, 9-etheroxime erythromycin A intermediate is provided. A preferred protecting group for the 2'-position is acetyl. 2'-protected, 9-etheroxime erythromycin A derivatives are also provided. Also disclosed is a method for inhibiting quaternary salt formation at the 3' amine without the need for 3'N-protecting groups.

Abstract: A process for preparing a compound of the structure I ##STR1## where A is oxygen and sulfur and R.sup.1 is selected from the group consisting of hydrogen, halogen, alkyl of one to six carbon atoms, alkoxy of one to six carbon atoms, and trifluoromethyl, and R.sup.2 is alkyl of one to four carbon atoms, comprising coupling a compound of formula II: ##STR2## where X is bromine or iodine, with an N-hydroxyurea compound of formula III: ##STR3## in the presence of a palladium catalyst followed by reaction of the product thus formed with an alkali metal isocyante.The compounds of formula I are inhibitors of the enzyme 5-lipoxygenase and are thus useful as therapeutic agents for the treatment of allergic and inflammatory disease conditions.

Abstract: A method for the separation of gibberellins from mixtures thereof by selective silylation or desilylation, as well as substantially pure gibberellins prepared thereby.