An organic amine salt compounds of general formula A.sup.n−[B.sup.m+].sub.p (I) is disclosed, wherein A.sup.n− is a CO.sub.2-donating anion with a valence of −n, wherein n=1, 2 or 3; each B.sup.m+ comprises: ammonium ion, hydrazinium ion and/or organic amine B cation; wherein $m=1\text{-}10;0<p\le \frac{n}{m};$
and wherein A.sup.n− is one or more selected from a group consisting of following anions: (a) carbamate orcarbazate; (b) carbonate; (c) formate; (d) bicarbonate; (e) organic monocarbonate; (f) organic poly-carbamate; (g) orthoformate; or (h) organic poly-carbonate. The compound of general formula (I) has at least one of hydroxyalkyl group linked to N atom, i.e., has alkanolamine residue. They can be used as polyurethane foaming agent, and most of them can be used as polystyrene foaming agent or polyvinyl choride foaming agent.

The present invention disclosed a method for preparing a thickener for tight oil and gas reservoir, which relieves damages. The technical solution includes the following steps: putting a three-flask in ice; adding perfluoroalkyl alcohol, P-toluenesulfonyl chloride and pyridine; reacting for 3 h at 0-20° C.; adding filter paper; ultrasonic dispersing for 1 h; removing the filter paper; washing the solution for 3-5 times by adding dilute hydrochloric acid to collect the intermediate product (I); adding 1,3-dihydroxy-propane-2-tert-butyl carbamate and the intermediate product (I) in another three-flask; adding potassium carbonate and N,N-dimethylformamide; reacting for 4 h at 40° C. to collect the intermediate product (II); adding trifluoroacetic acid and methylene chloride into the intermediate product (II); reacting at 45° C. for 2 h; extracting and vacuum drying; and adding 1,6-hexamethylene diisocyanate; reacting for 2 h to collect the final product (III).

The present invention disclosed a method for preparing a thickener for tight oil and gas reservoir, which relieves damages. The technical solution includes the following steps: putting a three-flask in ice; adding perfluoroalkyl alcohol, P-toluenesulfonyl chloride and pyridine; reacting for 3 h at 0-20° C.; adding filter paper; ultrasonic dispersing for 1 h; removing the filter paper; washing the solution for 3-5 times by adding dilute hydrochloric acid to collect the intermediate product (I); adding 1,3-dihydroxy-propane-2-tert-butyl carbamate and the intermediate product (I) in another three-flask; adding potassium carbonate and N,N-dimethylformamide; reacting for 4 h at 40° C. to collect the intermediate product (II); adding trifluoroacetic acid and methylene chloride into the intermediate product (II); reacting at 45° C. for 2 h; extracting and vacuum drying; and adding 1,6-hexamethylene diisocyanate; reacting for 2 h to collect the final product (III).

The invention provides methods of synthesizing compounds in an asymmetric or enantioenriched fashion, wherein the compounds are useful intermediates in the synthesis of viral protease inhibitors.

The invention provides methods of synthesizing compounds in an asymmetric or enantioenriched fashion, wherein the compounds are useful intermediates in the synthesis of viral protease inhibitors.

The invention provides methods of synthesizing compounds in an asymmetric or enantioenriched fashion, wherein the compounds are useful intermediates in the synthesis of viral protease inhibitors.

The invention provides methods of synthesizing a viral protease inhibitor in high yield, without using expensive catalysts or challenging reaction conditions.

The invention provides methods of synthesizing a viral protease inhibitor in high yield, without using expensive catalysts or challenging reaction conditions.

The invention provides methods of synthesizing a viral protease inhibitor in high yield, without using expensive catalysts or challenging reaction conditions.

The invention relates to a new process for producing useful intermediates for the manufacture of NEP inhibitors or prodrugs thereof, in particular NEP inhibitors comprising a γ-amino-δ-biphenyl-α-methylalkanoic acid, or acid ester, backbone, such as N-(3-carboxyl-1-oxopropyl)-(4S)-(p-phenylphenylmethyl)-4-amino-(2R)-methyl butanoic acid ethyl ester or salt thereof.