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Syntheses and CD studies of 5α‐cholesteno[3,2‐ d ]‐, ‐[2,3‐ d ]‐ and ‐[3,4‐ d ]pyrimidines
Author(s) -
Hasan Mashooda,
Rashid Naghmana,
Khan Khalid Mohammed,
Snatzke Günther,
Duddeck Helmut,
Voelter Wolfgang
Publication year - 1995
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.1995199505130
Subject(s) - chemistry , series (stratigraphy) , helicity , spectral line , sign (mathematics) , crystallography , stereochemistry , physics , quantum mechanics , mathematics , mathematical analysis , paleontology , biology
Syntheses of 5α‐cholesteno[3,2‐ d ]‐ ( 5a ), [2,3‐ d ]‐ ( 12a ), and [3,4‐ d ]pyrimidines ( 15a ) have been achieved by using hydroxymethylene derivatives of relevant cholestanones prepared from cholesterol ( 1 ). Their CD spectra exhibit at least three Cotton effects between 300 to 200 nm, a first CD band around 290, a second one around 260 and a third one around 220 nm. A quadrant rule is developed and applied to the determination of the sign of the first CD band, while a helicity rule is applicable to the third CD band. The first band is positive in the [3,2‐ d ] series, whereas it is negative in the [2,3‐ d ] and the [3,4‐ d ] series. The third band is negative in all three series.