Process for preparing 3-amino-1-butanol and related compounds
Disclosed herein are methods and processes of preparing 3-amino-(C 3-6 )-alkan-1-ol, including optically active 3-amino-(C 3-6 )-alkan-1-ol (e.g., optically active 3-amino-1-butanol such as (R)-3-amino-1-butanol). The 3-amino-(C 3-6 )-alkan-1-ol may be optionally substituted at the 1-position, e.g., with OH, alkoxy, O-acetyl, or silyl groups, among others. The processes include contacting a 1-nitro-(C 1-4 )-alkane with a vinyl source or an acetylene source in the presence of a base and a dehydrating agent to provide 3-(C 0-3 )-alkyl-2-isoxazoline; and/or contacting the 3-(C 0-3 )-alkyl-2-isoxazoline with hydrogen and a hydrogenation catalyst to provide 3-amino-(C 3-6 )-alkan-1-ol.
1 . A process comprising contacting nitroethane with ethylene in the presence of base triethylamine and dehydrating agent phenyl isocyanate to provide 3-methyl-2-isoxazoline.
2 . The process of claim 1 , wherein a molar ratio of the base triethylamine to nitroethane ranges from about 0.1:100 to about 20:100.
3 . The process of claim 1 , wherein a molar ratio of the dehydrating agent to the nitroethane ranges from about 1:1 to about 5:1.
4 . The process of claim 1 , wherein ethylene is present at a pressure of about 500 psi.
5 . The process of claim 1 , wherein the contacting occurs in the presence of benzene.
6 . The process of claim 1 , wherein the contacting occurs at an elevated temperature of about 40-70° C.
7 . The process of claim 1 , further comprising isolating and purifying the obtained 3-methyl-2-isoxazoline.
8 . The process of claim 1 , further comprising contacting 3-methyl-2-isoxazoline with a reducing agent to provide a reduced product 3-amino-1-butanol.
9 . The process of claim 8 , wherein the reducing agent is hydrogen and hydrogenation catalyst is Raney nickel.
10 . The process of claim 8 , wherein the contacting occurs at an elevated temperature of about 20-100° C.
11 . The process of claim 8 , further comprising isolating and purifying the obtained 3-amino-1-butanol.