PubMed · 5046519
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A Pines. 1972-08-05. Nitrazepam in chronic obstructive bronchitis.. https://doi.org/10.1136/bmj.3.5822.352-c
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[structure] Two general routes to 1,4-disubstituted-2,3,4, 5-tetrahydro-1H-3-benzazepines are described. Both routes utilize an appropriately functionalized phenethylamino alcohol as the penultimate intermediate: the first route makes use of the reductive amination of a benzyl alkyl ketone with alpha-(aminomethyl)benzyl alcohol, while the second route utilizes the addition of a Grignard reagent to the oxazolidine derived from a substitued phenylacetaldehyde and alpha-(methylaminomethyl)benzyl alcohol. In all cases studied, the cis-1,4-disubstituted-2,3,4, 5-tetrahydro-1H-3-benzazepine was obtained as the major product.
There is evidence that D1 and D2 dopamine receptors are co-expressed on some neurons. As a potential model of co-expression we examined Ntera-2 cells using RT-PCR, and showed that they express D2 but not D1 receptors. D2 dopamine receptor expression was confirmed by quinpirole inhibition of forskolin-stimulated cAMP formation. Absence of D1 dopamine receptors was confirmed by the inability of dopamine or SKF 81297 to increase cAMP.
4-Amino-2-benzazepin-3-ones have proven very useful for studying the biologically active conformations of peptides. The synthesis of Pht-Aba-Xaa-OH by reaction of the corresponding 1,3-oxazolidin-5-one with trifluoromethanesulfonic acid (TFMSA) has been reported in the literature. However, when this procedure was applied to the preparation of Pht-Hba(Bn)-Gly-OH 8, many byproducts were formed and the yield of the desired aminobenzazepinones 7 and 8 was very low. We report in this paper an efficient methodology for the synthesis of Pht-Hba(2,6-Cl2-Bn)-Gly-OH 17 starting from the commercially available tyrosine. In our procedure, the dipeptide Pht-Tyr(2,6-Cl2-Bn)-Gly-OH 15 is converted to the 1,3-oxazolidin-5-one 16 which then undergoes Friedel-Crafts cyclization in the presence of tin tetrachloride to afford the desired 4-phthalimido-1,3,4,5-tetrahydro-8-(2,6-dichlorobenzyloxy)-2-be nzazepin-3-one 17 in excellent yield.