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Chemical product profile

HONGKUN / PRODUCT DIRECTORY

Di-tert-butyl phosphite | CAS 749824-98-4

A tert-butyl-protected phosphorus reagent used in reported phosphate-intermediate synthesis, with phosphorus-species identity and ester-group integrity central to differentiating it from phosphate and trialkyl phosphite materials.

CAS749824-98-4
Molecular formulaC8H19O3P
Molecular weight194.21 g/mol

Product overview

Di-tert-butyl phosphite contains two tert-butoxy groups in a hydrogen phosphite framework. It must be distinguished from tri-tert-butyl phosphite and from oxidized di-tert-butyl phosphate, which have different compositions and reaction roles. CAS 749824-98-4 is listed for di-tert-butyl hydrogen phosphite in the FDA substance registry. For synthesis purchasing, identifying the phosphorus-containing components is particularly useful: total phosphorus analysis cannot show which species are present. A combination of structural identity, phosphorus-selective analysis and an appropriate quantitative assay can clarify the composition of a proposed grade.

Chemical identity

Chemical name
Di-tert-butyl phosphite
CAS number
749824-98-4
Molecular formula
C8H19O3P
Molecular weight
194.21 g/mol

Application context

Process research describes di-tert-butyl phosphite as a precursor to di-tert-butyl potassium phosphate, subsequently used in protected phosphate-intermediate chemistry. The oxidation step changes the phosphorus functionality while retaining the tert-butyl ester groups. These protected intermediates appear in routes toward phosphonooxymethyl prodrug structures. Reagent qualification should establish the starting phosphorus species and any phosphate already present, since pre-existing conversion products change the effective charge and reaction balance. The intended transformation also determines the acceptable residual alcohol, solvent and water levels.

Chemistry and synthetic role

Two tert-butoxy groups provide protected ester functionality at phosphorus. Phosphite, phosphate and tri-tert-butyl species should be distinguished by structure and suitable phosphorus analysis.

Quality review

Resolve phosphorus species

Consider 31P NMR or an equivalent method alongside quantitative assay.

Confirm two tert-butyl groups

Verify the diester identity rather than assuming equivalence with a triester.

Assess converted or cleaved material

Review phosphate and partial ester-cleavage products where relevant to the route.

Preparing a specification

Specify CAS and structure, phosphite assay, phosphorus-species profile, ester integrity and relevant alcohol, solvent and water limits.

Packaging and storage

Packaging and net weight are agreed for the selected grade, order quantity and destination. Check the actual supplier SDS and label for storage and transport requirements.

Documentation

Request a batch COA, SDS and the analytical methods for the acceptance criteria below. Confirm which supporting chromatograms and identity data are available from the selected manufacturer.

Procurement questions

Is total phosphorus sufficient?

It cannot distinguish the required phosphite from other phosphorus-containing compounds.

Is tri-tert-butyl phosphite the same reagent?

No. Its ester count and chemical identity differ.

Why specify phosphate impurities?

They represent a different phosphorus functionality and alter the amount of starting phosphite.

Technical sources
  1. PubChem CID 518693NCBI / PubChem
  2. Di-tert-butyl hydrogen phosphiteFDA GSRS
  3. Development of Efficient Processes for the Preparation of Di-tert-butyl Potassium Phosphate and Di-tert-butyl (Chloromethyl) PhosphateACS Organic Process Research & Development