DIHYDROXYMETHYLBORANE

Methylboronic acid; Methaneboronic acid;

PRODUCT IDENTIFICATION

CAS RN

13061-96-6

EINECS RN

FORMULA

MOLE WEIGHT

PHYSICAL AND CHEMICAL PROPERTIES

PHYSICAL STATE

white to off-white crystalline powder

MELTING POINT

91 - 94 C

BOILING POINT

DENSITY

SOLUBILITY IN WATER

pH

VAPOR DENSITY

REFRACTIVE INDEX

FLASH POINT

INCOMPATIBLE MATERIALS

Strong oxidizing agents. strong acids, strong bases.

Carbon oxides, Boron oxides.

NFPA RATINGS

SAFETY

HAZARD NOTES

EYE

SKIN

INGESTION

INHALATION

CHRONIC

TRANSPORT & REGULATORY INFORMATION

UN NO.

HAZARD SYMBOL

XI

RISK PHRASES

SAFETY PHRASES

OTHER INFORMATION

Structurally, boronic acids are trivalent boron-containing organic compounds that possess one alkyl substituent (i.e., a C–B bond) and two hydroxyl groups to fill the remaining valences on the boron atom (Figure 1.1). With only six valence electrons and a consequent deficiency of two electrons, the sp2-hybridized boron atom possesses a vacant p orbital. This low-energy orbital is orthogonal to the three substituents, which are oriented in a trigonal planar geometry. Unlike carboxylic acids, their carbon analogues, boronic acids are not found in nature. These abiotic compounds are derived synthetically from primary sources of boron such as boric acid, which is made by the acidification of borax with carbon dioxide. Borate esters, the main precursors for boronic acid derivatives, are made by simple dehydration of boric acid with alcohols. The first preparation and isolation of a boronic acid was reported by Frankland in 1860. By treating diethylzinc with triethylborate, the highly air-sensitive triethylborane was obtained, and its slow oxidation in ambient air eventually provided ethylboronic acid. Boronic acids are the products of the second oxidation of boranes. Their stability to atmospheric oxidation is considerably superior to that of borinic acids, which result from the first oxidation of boranes. The product of a third oxidation of boranes, boric acid, is a very stable and a relatively benign compound to humans. Their unique properties as mild organic Lewis acids and their mitigated reactivity profile, coupled with their stability and ease of handling, makes boronic acids a particularly attractive class of synthetic intermediates. Moreover, because of their low toxicity and their ultimate degradation into the environmentally friendly boric acid, boronic acids can be regarded as “green” compounds. They are solids that tend to exist as mixtures of oligomeric anhydrides, in particular the cyclic six-membered boroxines. For this reason and other considerations outlined below, the corresponding boronic esters are often preferred as synthetic intermediates. Although other classes of organoboron compounds have found tremendous utility in organic synthesis, this book focuses on the most recent applications of the more convenient boronic acid derivatives. For a comprehensive description of the properties and reactivity of other classes of organoboron compounds, interested readers may refer to a selection of excellent monographs and reviews by Brown, Matteson, and others. In the past two decades, the status of boronic acids in chemistry has risen from peculiar and rather neglected compounds to a prime class of synthetic intermediates. Much progress, described in hundreds of publications, has happened since the last review on boronic acid chemistry by Torssell in 1964. For instance, hopes for boronic acid based therapeutics have finally concretized. The recent approval of the anti-cancer agent Velcade®, the first boronic acid containing drug commercialized, further confirms the new status of boronic acids as an important class of compounds in chemistry and medicine. (source: http://media.wiley.com/product_data/excerpt/18/35273099/3527309918.pdf)

SALES SPECIFICATION

APPEARANCE

white to off-white crystalline powder

98.0% min

MELTING POINT

91 - 94 C