Benzoyl protecting groups

The consecutive reduction and cyclization of O-benzoyl protected 5-0-methylhexose 0-(terf-butyldiphenylsilyl)oxime (104) with dimethylphenylsilane in trifluoroacetic acid afforded a iV-hydroxypyrrolidine (105) ring system in good yield (equation 44). The mechanism involves a cascade of neighboring group participation steps involving the 0-benzoyl protecting groups " ". ... 

The first step consisted of the Mitsunobu etherification of an allyl alcohol with the resorcinol monoester, which afforded 102. Cleavage of the benzoyl protecting group released the phenol, which was then attached to the solid support. One-step cleavage of the THP group and bromination was achieved with PPhs/C Br4 to furnish 103. Nucleophilic substitution of the bromide with benzylamine was followed by acylation of the secondary amine wtith N-Boc-allylglycine 104, which resulted in the precursor 105, ready for the metathesis reaction this was performed with catalyst 101 to yield the final product 106. Either 1-octene or ethene was employed to generate 101. 

The Ninomiya, Rebek, Ortar, Ramage, and Kurihara plans involve hydrolysis of a benzoyl protecting group on the indole nitrogen atom the Oppolzer plan... 

Benzoperaza-crown-3 cyclophanes, table, 710 Benzoperaza-crown-4 cyclophanes, table. 718 Benzoperaza-crown-4 cyclophanes (miscellaneous), table, 739 Benzoperaza-crown-5 cyclophanes. table, 741 Benzoperaza-crown-6 cyclophanes, table, 742 Benzoperaza-crown-8 cyclophanes, table. 748 Benzopolyaza-crown synthesis. 407 Benzotetraaza-crown macrocycles, table, 437 Benzotriaza-9-crown-3, 152 Benzotriaza-crown macrocycles, table. 437 A-Benzoyl protecting groups. 49. 63, 359, 552... 

Some attention has been devoted to the use of photolabile protecting groups in DNA synthesis and a comparative study has been carried out. A particular problem is associated with the use of benzoyl protecting groups which react under the photolysis conditions. The solid support (120) has been demonstrated to produce yields of oligonucleotides which when compared to hydrolytic cleavage vary between 67% and 82%. ... 

The 2-(acetoxymethyl)benzoyl-protective group (4,5,6) has initially been used in the synthesis of particularly base-labile backbone modifications, such as phosphate methyl esters or methylphosphonates [51, 52], again thymine remains unprotected. Cleavage is achieved by elegant intramolecular reaction within 90 min at room temperature by use of potassium carbonate in dry methanol (Fig. 11). 

Figure 11.2-(Acetoxymethyl)benzoyl protective group is easily removed by potassium carbonate in anhydrous methanol at RT.

The benzoylated diribonucleoside of 6-ethoxycarbonyl-l,3-dihydro-imidazo[4,5-d][l,2]diazepin-2-one 197 treated with ammonia in methanol not only suffered deprotection of the benzoyl protective groups but also rearranged into IcP 198 derivative (86T1511). 

Potassium cyanide in 95% ethanol has been shown to be useful for removal of acetyl and benzoyl protecting groups from base-sensitive /6-D-galacto-pyranoside derivatives, and from oC-D-galactopyranosides bearing acid- and base-sensitive substituents such as isopropylidene or tosyl groups. 

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