• Archives of Pharmacal Research
• /
• v.16 no.2
• /
• pp.152-154
• /
• 1993

By using N-bromophthalimide (NBP) as halonium ion source for the Hofmann rearrangement, a series of primary amide could be ocnverted to the corresponding cabamate in excellent yields. So NBP was throught to be very effective and practical halonium ion source for the Hofmann rearrangement.

• Archives of Pharmacal Research
• /
• v.17 no.6
• /
• pp.490-491
• /
• 1994

• Archives of Pharmacal Research
• /
• v.15 no.4
• /
• pp.333-335
• /
• 1992

Hofmann rearrangement of a series of primary aliphatic and aromatic carboxamides 1a-1m with HgO-NBS (or dibromantin)R'OH-DMF gives corresponding carbamates 2a-2m in excellent yields.

• Archives of Pharmacal Research
• /
• v.16 no.2
• /
• pp.158-160
• /
• 1993

2-Oxazolidinones and 1,3-oxazine-2-ones, key moieties of new antiulcer agents, were prepared successfully by treating corresponding hydroxyamide with N-bromosuccinimide (NBS) and silveracetate in acetonitrile. From the fact that the methods for the preparation of hydoxy amides are versatile and such amides could be converted to the corresponding 2-oxazolid-iones and 1,3-oxazine-2-one under our reaction condition, we think that our method is very practical one for the preparation of such compounds. In addition, the above synthetic example affords a good evidence of the synthetic applicability of our improved Hofmann rearrangement.

• Archives of Pharmacal Research
• /
• v.17 no.1
• /
• pp.39-41
• /
• 1994

Various N,N'-disubstituted ureas 5 were easily prepared from the corresponding primary amide 1 by tratment with N-Bromophthalimide $(NBP)-AgOAc-RNH$_{2}$ 4 in dry N,N-dimrthylformamide (DMF). This reaction envolved the intemediate formation of isocyanate 3 from amide 1 via Hofmann rearrangement by treatment with AgOAc and NBP and nucleophilic addition of amine 4 to this isocyante 3. This method is simple enough to be applied to the synthesis of various N,N'-disubstututed ureas scale conviently.