Paul J. Edwards

Dispiroketals in synthesis (part 19)1: Dispiroketals as enantioselective and regioselective protective agents for symmetric cyclic and acyclic polyols.

Abstract The enantioselective preparation of both enantiomers of a C2-symmetric diphenyl-bi-dihydropyran 3 and 4 is described. The application of enantiopure bi-dihydropyrans 1 – 4 towards the simultaneous enantioselective differentiation and regioselective protection of a range of cyclic and acyclic symmetrical polyols (23, 37, 43, 45, 54, 61 and 66) is investigated. Several deprotections utilising trifluoroacetic acid (TFA) and a transketalisation with acidic glycerol are presented.

Dispiroketals in synthesis (Part 17): Regioselective protection of D-glucopyranoside D-galactopyranoside and D-mannopyranoside substrates.

Abstract Chiral recognition of enantiomeric trans-1,2-diol relationships leading to regioselective formation of 1,8,13,16-tetraoxadispiro[5.0.5.4] hexadecanes (dispiroketals) of various D -glucopyranoside, D -galactopyranoside and D -mannopyranoside substrates is described. Regioselectivity is achieved using the enantiomerically pure disubstituted tetrahydro-6,6′-bi-2H-pyrans 1, 2, 3, 4 and 5. Facile removal of the dispiroketal protecting group from a number of the sugar adducts has been achieved.

Dispiroketals in synthesis (Part 11): Concomitant enantioselective and regioselective protection of 2,5- dibenzoyl-myo-inositol☆

2,5-Dibenzoyl-myo-inositol, a symmetrical polyol, may be simultaneously enantioselectively and regioselectively protected using the chiral dienes (1), (2) and (3). Deprotection, to afford D or L-1,6-tetra-O-benzyl-myo- inositol (8) and (12) respectively, was achieved using trifluoroacetic acid.

Dispiroketals in synthesis (part 9): Resolution of 1,2-diols using a C2-symmetric diphenyltetrahydrobipyran.

Abstract A series of 1,2-diols were resolved by the enantioselective formation of the thermodynamically most stable dispiroketal using (2 R ,2′ R ) and (2 S ,2′ S ), 2,2′-diphenyl-3,3′,4,4′-tetrahydro-6,6′-bi-2 H -pyran 2 and 3 . Deprotection was achieved using a metal ammonia reduction to liberate the resolved diols.

Fibroblast Growth Factor Signalling and Cyclin D1 Function are Necessary for Normal Mammary Gland Development during Pregnancy

A number of growth factors, growth factor receptors and cell cycle regulatory proteins have been implicated in the genesis of mammary carcinomas both in animal models as well as in human breast tumour samples. Studies on the development of the mammary gland has revealed that several of the proto- oncogenes, or their closely related gene-family members, have a function in the normal growth and differentiation of the gland. In this review the role of fibroblast growth factor signalling and the critical requirement for the cell cycle regulator, cyclin D1 is discussed with respect to their normal function in mammary gland development and abnormal role in mammary carcinogenesis.

Dispiroketals in synthesis. Part 23.1 A newroute to (+)-D-conduritol B frommyo-inositol

Using n(2S,2′S)-2,2′-diphenyl-6,6′-bi(3,4-dihydro-2 nH-pyran) to effect a simultaneous nprotection–resolution of a myo-inositol nderivative, a new synthesis of n(+)-D-conduritol B has been nachieved.