Syntheses of O⁶‐Alkyl‐ and Arylguanine Derivatives: Nucleobase Adducts Derived from Styrene 7,8‐ and 3,4‐Oxides

Abstract

A series of O6‐alkyl and ‐arylguanine derivatives that may be formed in vivo after exposure to styrene has been prepared by reaction of 6‐(4‐aza‐1‐azoniabicyclo[2.2.2]octyl)‐purine with alkoxides and aryloxides, respectively. Themonoprotected diols 2‐allyloxy‐ or 2‐benzyloxy‐1‐phenylethanol and 2‐allyloxy‐ or 2‐benzyloxy‐2‐phenylethanol were used as synthetic equivalents of styrene 7,8‐oxide. 4‐Vinylphenol, 2‐(4‐hydroxyphenyl)ethanol and 4‐hydroxyphenylacetic acid were used as synthetic equivalents of arene oxide metabolites of styrene, i. e., styrene 3,4‐oxide, 4‐(2‐hydroxyethyl)benzene 1,2‐oxide and 4‐carboxymethylbenzene 1,2‐oxide, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Polymethylhydrosiloxane

“…96 This technique has been exploited in natural product synthesis, for example, during synthesis of (+)-2-deoxyolivin (eq 48) 97 and in the synthesis of nucleobase adducts. 98 Other deallylation examples have also been reported. 99 PMHS has also been used in radical de-oxygenation reactions of pentafluorophenylthionecarbonates during an approach to the natural product widderol (eq 49).…”

Unexpected rearrangement of enantiomerically pure 3‐aminoquinuclidine as a simple way of preparing diastereomeric octahydropyrrolo[2,3‐c]pyridine derivatives

“…14 In general, tertiary bicyclic nitrogen-containing compounds such as 1,4-diazabicyclo[2.2.2]octane (DABCO) (6), without the 3-amino group found in 3-aminoquinucli-dine, readily displace chlorines of a-chloroheterocycles, including pyridine (in the form of nicotinic acid), purine, triazine, and guanine. [15][16][17][18][19] These active carbon centers can then react with nucleophiles such as alkoxides to form various ethers (generalized Scheme 1). The reaction of 2,4-dichloroquinazoline with N-methylpyrrolidine gives N-(2-chloro-4-quinazolinyl)-N-methylpyrrolidinium chloride, which is a stable betaine (Scheme 2).…”