S.F. Dyke

α-Aminonitriles—I: A simple synthesis of deoxybenzoins

Abstract A method is described, involving an acyl anion equivalent, for the preparation of deoxybenzoins that are inaccessible by the more usual methods.

1,2-dihydroisoquinolines—XI: Further berbine syntheses

Abstract New syntheses of tetrahydroberberine and tetrahydropalmatine are described and some other potential routes to the berbine skeleton are explored.

1,2-dihydroisoquinolines—VII : New syntheses of avicine and nitidine derivatives☆

Abstract Synthetic routes to the benzo[c]phenanthridine ring system have been investigated, and new syntheses of oxyavicine ( 2a ), 2,3-dimethoxy-8,9-methylenedioxybenzo[c]phenanthridine ( 5c ) and 2,3,8,9-tetramethoxybenzo[c]phenanthridine ( 5a ) are described.

1,2-Dihydroisoquinolines X : The cyclization of benzylaminoacetaldehyde dialkylacetals

Abstract The cyclization of some benzylaminoacetaldehyde dialkyl acetals has been examined and their utilization for the preparation of various isoquinoline derivatives studied. Some observations on the mechanism of cyclization of these acetals have also been made.

The synthesis of 5-hydroxyberbine derivatives

Abstract The syntheses of 5-hydroxy-2,3,10,11-tetramethoxyberbine (4, R1 = OMe; R2 = OH) and 5-hydroxy-2,3-methylenedioxy-10,11-dimethoxyberbine(4, R1 + R1 = CH2O2R; = OH)aredescribed. The structures have been established by chemical and spectral methods and, in the former case, the relative stereochemistry has been elucidated. These are the first examples of 5-hydroxyberbine derivatives to be prepared.

The synthesis of isopavine alkaloids—III

Abstract The two isopavines (le and lf) have been synthesised, and the former has been found to correspond to the structure of the alkaloid reframoline. The two related pavines were isolated and identified as by-products. In one case some evidence was obtained for a C1→C3-benzyl migration in the isoquinoline system. Although it has proved to be impossible to distinguish between the two isopavines by spectral methods, a significant difference was observed in the UV spectra of the derived methine bases in alkaline solution.

1,2-dihydroisoquinolines—V : A simple benzo[c]phenanthridine ring synthesis☆

Abstract The known 2 2,3,8,9-tetramethoxybenzo[c]phenanthridine ( 33 ) has been synthesized in a simple procedure utilizing a 1,2-dihydroisoquinoline and a photochemical ring-closure reaction.

Some Diels-Alder reactions with 4-vinyl isoquinoline derivatives

Abstract The first preparation of 4-vinylisoquinoline derivatives is described. 1,4-Cycloadducts have been obtained by their interaction with the dienophiles maleic anhydride, acrylic acid, p -benzoquinone, propriolic acid and benzyne. The structures of the adducts have been assigned on the basis of chemical, but mainly spectroscopic evidence.

1,2-dihydroisoquinolines—VIII : Rearrangement—II☆

Abstract The acid promoted rearrangement of 1-allyl-2-methyl-1,2-dihydroisoquinoline to the corresponding 3-allyl-2-methyl-3,4-dihydroisoquinoline salt has been observed and the behaviour of 1-benzyl-2-methyl-1,2-dihydroisoquinoline and 2-methyl-1,2-dihydropapaverine towards various conditions of acid concentration and temperature has been studied.

1,2-dihydroisoquinolines—XV : Rearrangement III

Abstract The acid-catalysed rearrangement of a 1-allyl-1,2-dihydroisoquinoline into a 3-allyl-3,4-dihydroisoquinolinium salt has been shown to occur in an intra 1-propargyl-1,2-dihydroisoquinoline into a 3-allenyl-3,4-dihydroisoquinolinium salt is also described.