Abstract: This invention relates to 1,3-dihydroxy-20,20-dialkyl-vitamin D3 analogs of Formula (I): 1

Abstract: Fluorinated Vitamin D.sub.3 analogs, intermediates for their preparation, compositions comprising the analogs and methods of treatment of osteoporosis and related conditions with these and related analogs are provided.

Abstract: The process of the invention comprises reacting a C-22-halo-23,24-bisnorsteroid or C-22-halo-23,24-bisnor-9,10-secosteroid with a nickel complex of an electron withdrawing alkene of the formula ##STR1## wherein R.sub.1 is hydrogen, hydroxycarbonyl, lower alkoxycarbonyl, lower alkylcarbonyl or unsubstituted or substituted lower alkyl, and R.sub.2 is hydroxyl, lower alkoxy, or unsubstituted or substituted lower alkyl, to yield a C-25 or C-26 precursor of the formula ##STR2## which is appropriately functionalized for conversion into the corresponding steroid or secosteroid by treatment as hereinafter described.

Abstract: The process of the invention comprises reacting a C-22-halo-23,24-bisnorsteroid or C-22-halo-23,24-bisnor-9,10-secosteroid with a nickel complex of an electron withdrawing alkene of the formula ##STR1## wherein R.sub.1 is hydrogen, hydroxycarbonyl, lower alkoxycarbonyl, lower alkylcarbonyl or unsubstituted or substituted lower alkyl, and R.sub.2 is hydroxyl, lower alkoxy, or unsubstituted or substituted lower alkyl,to yield a C-25 or C-26 precursor of the formula ##STR2## which is appropriately functionalized for conversion into the corresponding steroid or secosteroid by treatment as hereinafter described.

Abstract: The process of the invention comprises reacting a C-22-halo-23,24-bisnorsteroid or C-22-halo-23,24-bisnor-9,10-secosteroid with a nickel complex of an electron withdrawing alkene of the formula ##STR1## wherein R.sub.1 is hydrogen, hydroxycarbonyl, lower alkoxycarbonyl, lower alkylcarbonyl or unsubstituted or substituted lower alkyl, and R.sub.2 is hydroxyl, lower alkoxy, or unsubstituted or substituted lower alkyl,to yield a C-25 or C-26 precursor of the formula ##STR2## which is appropriately functionalized for conversion into the corresponding steroid or secosteroid by treatment as hereinafter described.

Abstract: The invention is directed to a process and intermediates for the preparation of benzopyrans such as racemic-6-acetyl-7-[5-(4-acetyl-3-hydroxy-2-propylphenoxy)pentyloxy]-3, 4-dihydro-2H-1-benzopyran-2-carboxylic acid.

Abstract: The invention is directed to a process and intermediates for the preparation of benzopyrans such as racemic-6-acetyl-7-[5-(4-acetyl-3-hydroxy-2-propylphenoxy)pentyloxy]-3,4-d ihydro-2H-1-benzopyran-2-carboxylic acid.

Abstract: A method for the synthesis of 2',3'-dideoxycytidine comprising a novel procedure of bromoacetylating cytidine to yield novel intermediates which are subsequently reduced and hydrogenated by novel procedures to yield 2',3'-dideoxycytidine.

Abstract: A process for the preparation of aromatic ethers by the bromination of a compound of the formula ##STR1## wherein R.sub.1, independently, is hydrogen, hydroxy, lower alkoxy, lower alkyl; m is an integer from 1-4, and A is --CHO, --COOR.sub.3 or lower alkyl, and subsequently treating the reaction product of the bromination step with an alkali metal alkoxide in the presence of cuprous halide or oxide, is described.

Abstract: A novel procedure for the preparation of carotenoids, particularly vitamin A, employing .pi.-allyl transition metal complexes. Novel carotenoid intermediates are also disclosed.