The present invention relates to novel, powerful reducing agents, lithium aminoborohydrides which are prepared by addition of BH.sub.3 .cndot.THF to the corresponding dialkylamine at 25.degree. C. to give the intermediate amineborane complex. Subsequent deprotonation by strong base, e.g. n-BuLi, yields the aminoborohydride quantitatively. Lithium aminoborohydrides are powerful reducing agents, comparable in strength to lithium aluminum hydride. The activity is determined by the dialkylamine. Lithium pyrrolidinoborohydride has unique activity and selectivity in its reducing properties. Esters, lactones and anhydrides are reduced cleanly at 25.degree. C. to give the corresponding alcohols, while carboxylic acids are not reduced. Test reductions show that lithium pyrrolidinoborohydride is also capable of reducing a wide range of functional groups including amides, epoxides, oximes, nitriles and halides.
This is a continuation of copending application of Ser. No. 07/848,427 filed on Mar. 6, 1992, now abandoned, which is a continuation-in-part of the application Ser. No. 07/847,171 filed on Mar. 6, 1992, now abandoned.
A process is disclosed for preparing a compound of the Formula or a complex thereof of the Formula wherein M is Li, Na, K, Rb or Cs; R.sup.1 is H, an aliphatic C.sub.1 to C.sub.5 residue, an aromatic residue, or a cycloaliphatic residue; R.sup.2 is H, an aliphatic C.sub.1 to C.sub.5 residue, an aromatic residue, or a cycloaliphatic residue; or R.sup.1 and R.sup.2 form a common cyclic residue; L is a dipolar aprotic solvent; and x is a numerical value from 0.1 to 5, which comprises the steps of: (a) where the compound of the Formula M(R.sup.1 R.sup.2 N.BH.sub.3) is prepared, reacting a compound of the Formula with an alkali metal or an alkali metal amide in a non-polar aliphatic or aromatic solvent; or (b) where the complex of the Formula M(R.sup.1 R.sup.2 N.BH.sub.3).xL is prepared, reacting the compound of the Formula with an alkali metal or an alkali metal amide in the dipolar, aprotic solvent or is a mixture of the dipolar aprotic solvent and the non-polar aliphatic or aromatic solvent.
The present invention concerns an improved optical method and optical sensing device for determining the levels of polyhydroxyl-substituted organic molecules in vitro in aqueous or organic media. Specifically, a dye is combined with an conjugated nitrogen-containing aromatic heterocyclic aromatic boronic acid-substituted bis-onium compound in the presence of a sugar, such as fructose or glucose. The viologens are preferred as the aromatic conjugated nitrogen containing boronic acid substituted compounds. The method is useful to determine sugar levels in fermentation and process streams.
The present invention concerns an improved optical method and optical sensing device for determining the levels of polyhydroxyl-substituted organic molecules in vitro and/or in vivo in aqueous media. The range of detection is between about 400 and 800 nm. In particular, a sensory devise is implemented in a mammal to determine sugar levels. Specifically, a dye is combined with a conjugated nitrogen-containing heterocyclic aromatic boronic acid-substituted bis-onium compound in the presence of a sugar, such as fructose or glucose. The viologens are preferred as the aromatic conjugated nitrogen-containing boronic acid substituted compounds. The method is useful to determine sugar levels in a human being.
The present invention concerns an improved optical method and optical sensing device for determining the levels of polyhydroxyl-substituted organic molecules in vivo in aqueous media. Specifically, a dye is combined with a conjugated nitrogen-containing heterocyclic aromatic boronic acid-substituted bis-onium compound in the presence of a sugar, such as fructose or glucose. The viologens are preferred as the aromatic conjugated nitrogen-containing boronic acid substituted compounds. The method is useful to determine sugar levels in a human being.
