Biotage® PS-TsNHNH2

Committed to preserving our shared environment – further details available on request.

Can be used in processes in compliance with cGMP standards.

Manufacture of consumables is accredited by the world renowned British Standards Institute.

Flexible supply chains, back up manufacturing and warehousing ensures supply risk reduction

Can be used in processes in compliance with GLP standards.

Products which are scaleable from lab or development to process scale.

Long to indefinite product shelf life, reduced process risk.

Supports pharma guidelines for reducing elemental impurities in APIs.

Further extractable information provided on request.

Raw materials certified free of materials of human or animal origin.

Chemical substances used in our manufacturing process do not require registration.

Able to withstand mechanical stirring and heating under normal reaction conditions.

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Background

Biotage® PS-TsNHNH2 is a resin-bound equivalent of p-toluenesulfonyl hydrazide and is an excellent scavenger of aldehydes and ketones. Comparison with other polymeric benzyl hydrazide showed PS-TsNHNH2 was a superior scavenger for carbonyls and much more stable to storage (the benzyl hydrazide resin decomposed on storage).

General Conditions for Use

Removal of excess carbonyls from solution generally requires a three-fold excess of PS-TsNHNH2. Addition of a catalytic amount of HOAc (5–10%) may be required for ketones and hindered aldehydes. HOAc is also required for sequestering aldehydes in DMF. Complete removal of common aldehydes occurs in 0.5 to 3 h and removal of a ketone takes from 2 to 16 h. Elevated temperatures were required for hindered ketones (e.g. 2,6-dimethylcyclohexanone). Upon completion of the scavenging, the resin is rinsed with a suitable solvent (i.e. those which swell polystyrene), and the product is isolated by concentration.

Application to Grignard Reactions

PS-TsNHNH2 was successfully used to work up the synthesis of alcohols by addition of a Grignard reagent to aldehydes. PS-TsNHNH2 is also potentially useful as a polymer-supported reagent. Supported sulfonyl hydrazones, formed by condensation with carbonyl compounds, can be utilized in further synthetic transformations. The high accessibility of tosyl hydrazide functional groups in PS-TsNHNH2 afford high synthetic fidelity relative to reported systems.

Reductive Amination

This scavenger can be applied to the rapid clean-up of tertiary amines prepared through reductive amination using MP-Triacetoxyborohydride and microwave irradiation.

Representative Procedures

Aldehyde Scavenging

PS-Tosyl Hydrazine (0.6 g) was added to a mixture of 3-methoxybenzylaldehyde (20 μL, 1.5 mmol) and naphthalene (15 mg; internal standard) in THF (2 mL). This mixture was stirred for 30min, then filtered and washed with MeOH (8 mL). The filtrate was concentrated and analyzed by RP-HPLC.

Reductive Amination

To a solution of the amine (0.5 mmol) and 3-methoxybenzylaldehyde (0.7 mmol) in a solution of THF and 5 % Acetic acid (2 mL) was added MP-Triacetoxyborohydride (523 mg, 2.39 mmol/g, 1.25 mmol). The vial was capped and heated to 120 ºC for 6 min, then PS-TsNHNH2 (0.6 g) added. The vial mixture was heated to 100 ºC for 5 min, after which the reaction mixture was filtered. The solid was washed with a 1:1 solution of THF/MeOH (10 mL) and the filtrate was concentrated to afford product.