An asymmetric diamine suitable for preparing a soluble polyimide and a method for preparing the same, including a compound represented by the following formula (1): ##STR00001##
wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are, independently of each other, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, and A and B are, independently of each other, a nitro group or an amino group. Further, a method for preparing the compound represented by the aforesaid formula (1).

Amine N-oxide compounds having formula (I) or (II), a preparation method, and a surfactant containing the compounds:

##STR00001##

R.sup.1 is a hydrocarbon residue with 4 to 26 carbon atoms and optionally at least one O or S; R.sup.2, R.sup.3 and R.sup.5 are each hydrogen, R.sup.1O, R.sup.8 and in formula (I) also optionally CH.sub.2N.sup.+(O.sup.?)R.sup.6R.sup.6; R.sup.8 is a hydrocarbon radical with 1 to 26 carbon atoms and optionally at least one O or S; R.sup.4 is hydrogen or R.sup.8; and each R.sup.6 is a hydrocarbon radical with 1 to 6 carbon atoms and optionally at least one N, O or S. Optionally two radicals R.sup.6 on the same nitrogen atom are connected to form a five- or six-membered, nitrogen-containing ring, or optionally radical(s) R.sup.6 of a moiety N.sup.+(O.sup.?)R.sup.6R.sup.6 may be linked to radical(s) R.sup.6 of another formula (I) molecule, forming a bridge having the structure

##STR00002##

and a dimer of formula (II).

Amine N-oxide compounds having formula (I) or (II), a preparation method, and a surfactant containing the compounds:

##STR00001##

R.sup.1 is a hydrocarbon residue with 4 to 26 carbon atoms and optionally at least one O or S; R.sup.2, R.sup.3 and R.sup.5 are each hydrogen, R.sup.1O, R.sup.8 and in formula (I) also optionally CH.sub.2N.sup.+(O.sup.?)R.sup.6R.sup.6; R.sup.8 is a hydrocarbon radical with 1 to 26 carbon atoms and optionally at least one O or S; R.sup.4 is hydrogen or R.sup.8; and each R.sup.6 is a hydrocarbon radical with 1 to 6 carbon atoms and optionally at least one N, O or S. Optionally two radicals R.sup.6 on the same nitrogen atom are connected to form a five- or six-membered, nitrogen-containing ring, or optionally radical(s) R.sup.6 of a moiety N.sup.+(O.sup.?)R.sup.6R.sup.6 may be linked to radical(s) R.sup.6 of another formula (I) molecule, forming a bridge having the structure

##STR00002##

and a dimer of formula (II).

An asymmetric diamine suitable for preparing a soluble polyimide and a method for preparing the same, including a compound represented by the following formula (1):

##STR00001##

wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are, independently of each other, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, and A and B are, independently of each other, a nitro group or an amino group. Further, a method for preparing the compound represented by the aforesaid formula (1).

An asymmetric diamine suitable for preparing a soluble polyimide and a method for preparing the same, including a compound represented by the following formula (1):

##STR00001##

wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are, independently of each other, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, and A and B are, independently of each other, a nitro group or an amino group. Further, a method for preparing the compound represented by the aforesaid formula (1).

A process of dissolving ##STR00001##
in a solvent to produce a first mixture. To the first mixture a reagent is added to produce a second mixture. A HRR is then added to the second mixture to produce a third mixture. The third mixture is then refluxed to produce ##STR00002##

A process of dissolving ##STR00001##
in a solvent to produce a first mixture. To the first mixture a reagent is added to produce a second mixture. A HRR is then added to the second mixture to produce a third mixture. The third mixture is then refluxed to produce ##STR00002##

A process of dissolving [6,6]-phenyl-C.sub.60-butyric-N-2-dimethylaminoethyl ester in a solvent to produce a first mixture. A reagent is added to the first mixture to produce a second mixture. The second mixture is then refluxed to produce [6,6]-phenyl-C.sub.60-butyric-N-2-trimethylammonium ethyl ester iodide.

A process of dissolving [6,6]-phenyl-C.sub.60-butyric-N-2-dimethylaminoethyl ester in a solvent to produce a first mixture. A reagent is added to the first mixture to produce a second mixture. The second mixture is then refluxed to produce [6,6]-phenyl-C.sub.60-butyric-N-2-trimethylammonium ethyl ester iodide.

The present invention discloses a Y-type discrete polyethylene glycol derivative and a preparation method thereof, which has the advantages of determined molecular weights and the number of chain segments, and can avoid the defect of heterogeneity of a PEG derivative, meanwhile the preparation method has simple steps, mild conditions, without need for strictly anhydrous environment or performing protection and deprotection steps. In addition, the Y-type discrete polyethylene glycol derivative of the present invention may increase the water solubility of the discrete polyethylene glycol, and solve the problem of insufficient water solubility of the discrete polyethylene glycol-modified insoluble drug caused by an increase of the loading capacity.