Crystalline Sitagliptin Hydrochloride Process Without Ether Isolation

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Solution Overview

Problem

Existing processes for preparing sitagliptin hydrochloride monohydrate are not suitable for industrial production and often use hazardous solvents like diethyl ether, posing safety and handling challenges.

Innovation Solution

A process involving the deprotection of Boc-sitagliptin with hydrochloric acid or hydrogen chloride in ethanol, followed by drying to form anhydrous sitagliptin hydrochloride and then hydrating under controlled humidity to produce crystalline sitagliptin hydrochloride monohydrate, using environmentally friendly solvents like ethanol and water.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If diethyl ether is used as solvent in the crystallization process, then crystalline sitagliptin hydrochloride monohydrate can be obtained, but the process becomes hazardous due to high volatility and flammability

Engineering Contradiction:
Improvecrystal form purityVSAvoidsafety hazards
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the solvent parameter from diethyl ether to ethanol, fundamentally altering the chemical properties of the system. Ethanol maintains the ability to produce crystalline sitagliptin hydrochloride monohydrate while eliminating the safety hazards associated with diethyl ether's high volatility and flammability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces expensive and hazardous diethyl ether with cheaper and safer ethanol. Ethanol is less volatile, non-flammable under normal conditions, and more environmentally friendly, making it suitable for industrial-scale production while maintaining product quality.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Manufacturing precision

If multiple solvents and complex crystallization steps are used, then crystalline sitagliptin hydrochloride can be obtained, but the process complexity increases

Engineering Contradiction:
Improvecrystal form controlVSAvoidprocess steps
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates unnecessary process steps from the conventional multi-step procedure. By using ethanol as the sole solvent for both dissolution and crystallization, the patent removes the need for separate solvent exchange steps and complex crystallization protocols, simplifying the overall process while maintaining crystal form control.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Ethanol serves multiple functions in the patent: it acts as the dissolution solvent, the crystallization solvent, and the washing solvent. This multi-functionality eliminates the need for multiple different solvents and reduces the number of process steps required to obtain crystalline sitagliptin hydrochloride monohydrate.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If hazardous solvents are used in the process, then the desired crystalline product can be obtained, but environmental and safety concerns arise

Engineering Contradiction:
Improveproduct purityVSAvoidtoxicity
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical parameter of the solvent from hazardous diethyl ether to safe ethanol. This fundamental parameter change maintains the ability to produce pure crystalline sitagliptin hydrochloride monohydrate while eliminating toxicity and environmental harm, making the process suitable for industrial application.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The process achieves high purity sitagliptin hydrochloride monohydrate with low impurity content, suitable for industrial production, and avoids the use of toxic solvents, ensuring safety and efficiency.

Implementation Method 1

deprotecting compound of formula (II) with a solution of hydrochloric acid or hydrogen chloride in a solvent

Methodology Applied
Scientific EffectChemical reaction (deprotection): Chemical Bonding

Implementation Method 2

drying the crystalline solid product obtained in step a)

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

hydrating the product obtained in step b) to obtain crystalline sitagliptin hydrochloride monohydrate

Methodology Applied
Scientific EffectHydration: Hydrates

Data Source

PatentEP4469459B1Process for preparing crystalline sitagliptin hydrochloride monohydrate
Publication Date: 2026.01.21 ZAKLADY FARMACEUTYCZNE POLPHARMA SA
  • EP4469459B1 patent drawingFigure 1
  • EP4469459B1 patent drawingFigure 2
  • EP4469459B1 patent drawingFigure 3

AI summary

The present invention relates to a process for preparing crystalline sitagliptin hydrochloride monohydrate, compound of formula (IV) from compound of formula (II), Boc sitagliptin, without the need of isolating sitagliptin free base.