Mechanistic studies on the total synthesis of heterocyclic steroids: Attempts of synthesis of 4,6-diazasteroids

Total synthesis of 2-azaestratrienes

“…(±)-3-Methoxy-2-azaestra-l,3,5(10),8,14-pentaen-17-ol (11). To 3.75 g (0.013 mol) of 10 in 125 mL of methanol was added 1.4 g of sodium borohydride in portions at room temperature.…”

“…Reduction of the ketone 10 with sodium borohydride in methanol gave (±)-3-methoxy-2-azaestra-1,3,5 (10),8,14pentaen-17-ol (11). This compound underwent catalytic hydrogenation over palladium on calcium carbonate to afford the desired 14a product 13 in 90% yield.…”

“…The exocyclic triene 22 is apparently unstable to these reaction conditions, and alternate methods for this transformation were investigated. It was found that by using concentrated sulfuric acid at room temperature, 21 is smoothly cyclized with subsequent isomerization of the double bonds into conjugation with the 17-ketone to afford 3-methoxy-1 l-methyl-2-azaestra-l,3,5 (10),9 (11),8 (14),15-hexaen-17-one (23) in yields up to 90%.2°In contrast to the 11-methylene isomer of the carbocyclic series,17 this tetracyclic hexaene is quite stable at room temperature, apparently due to the conjugation of the double bonds with the carbonyl. where hydrogenation was shown to produce the lid-methyl isomer.21…”

cis-4,4'-Stilbenediols. Synthesis from dienestrol, structure, and photocyclization to dihydrophenanthrenes

“…The UV spectra were recorded on a Cary Dienestrol (3a). NMR 1.50 (d, CHCH3, J = 6.5 Hz), 5.37 (q, CHCH3, J = 6.5 Hz), 6.65-7.3 (m, aromatic protons), 8.45 (s, OH); mass spectrum, m/e (relative intensity) 266 (100), 251 (50), 237 (36), 121 (31), 145 (25), 267 (22), 107 (22), 210 ( 14), 236 (13), 252 (11), 173 (11).…”