Morpholine Pyrimidine Synthesis via Enzymatic Sulfur Oxidation
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Solution Overview
Problem
The existing synthetic route for the compound 4-{4-[(3R)-3-methylmorpholin-4-yl]-6-[1-((R)-S-methylsulfonimidoyl)cyclopropyl]pyrimidin-2-yl}-1H-pyrrolo[2,3-b]pyridine is inefficient, costly, and environmentally unsustainable due to its lengthy sequence, challenging cyclopropanation steps, and the use of expensive reagents like rhodium, making it unsuitable for commercial-scale production.
Innovation Solution
A novel synthetic route involving enzymatic asymmetric sulphur oxidation, photo-catalyzed reactions, and reduced linear sequence stages is developed, utilizing oxidative enzymes, photo-catalysts, and alternative reagents to streamline the synthesis, reducing the number of steps and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the existing synthetic route is used, then the compound can be produced, but the synthesis requires 15 stages with a 14-stage linear sequence, making it inefficient and costly for commercial production
Solution Approach 1:
The patent segments the synthesis into modular stages, particularly isolating the cyclopropanation step as a distinct module that can be optimized independently. The route is divided into: (a) preparation of cyclopropyl intermediate via asymmetric sulfoxidation, (b) preparation of pyrimidine intermediate, and (c) final coupling to form the compound of Formula (I). This modular approach reduces the linear sequence from 14 stages to 7 stages while maintaining product quality.
Solution Approach 2:
The patent performs preliminary actions by preparing key intermediates (cyclopropyl intermediate with sulfoximine group and pyrimidine intermediate) before the final coupling step. The asymmetric sulfoxidation is performed early on the cyclopropyl intermediate, establishing the chiral center and sulfoximine functionality before subsequent transformations. This preliminary preparation of functionalized intermediates streamlines the overall synthesis and reduces the number of stages required.
2Ease of manufacture
If the existing synthetic route is used, then the compound can be produced, but expensive reagents like rhodium are required, increasing production costs
Solution Approach 1:
The patent replaces expensive rhodium catalyst with more economical catalyst systems. Specifically, the asymmetric sulfoxidation employs organic catalysts or enzymes (such as cyclohexanone monooxygenase or Ti-tartrate catalysts) instead of rhodium. The Suzuki coupling uses palladium catalysts which are generally more abundant and less expensive than rhodium. This substitution of expensive reagents with cheaper alternatives significantly reduces production costs while maintaining synthetic efficiency.
Solution Approach 2:
The patent changes the chemical parameters of the catalytic system by transitioning from rhodium-based catalysis to enzyme-catalyzed or organocatalytic asymmetric sulfoxidation. This parameter change involves selecting different catalyst types (enzymes vs. metal complexes), different reaction conditions (aqueous/organic solvent systems), and different mechanistic pathways (biocatalytic vs. organometallic). These parameter changes enable the use of more cost-effective catalytic systems suitable for commercial production.
3Manufacturing precision
If the existing synthetic route is used, then the compound can be produced, but the cyclopropanation step is very challenging requiring continuous stirred tank process with challenging work up and only moderate yield with many impurities
Solution Approach 1:
The patent replaces the mechanical continuous stirred tank process with enzyme-catalyzed asymmetric sulfoxidation. Instead of using mechanical stirring and complex work-up procedures for cyclopropanation, the invention employs biocatalytic oxidation that proceeds under milder conditions with easier work-up. The enzymatic process occurs in aqueous or water-miscible solvent systems, simplifying phase separations and purification steps compared to traditional organic-phase cyclopropanation methods.
Solution Approach 2:
The patent changes the reaction parameters of the cyclopropanation step by using enzyme catalysis instead of traditional metal-catalyzed or organometallic methods. This involves changing the temperature regime (often lower temperatures for enzymatic reactions), solvent system (aqueous or water-miscible solvents), and catalytic mechanism (biocatalytic oxidation). These parameter changes result in higher yields, improved stereoselectivity, and simplified work-up procedures with fewer impurities requiring removal.
4Productivity
If the existing synthetic route is used, then the compound can be produced, but the route is not convergent with longest linear sequence of 14 stages, making it unsuitable for commercial scale
Solution Approach 1:
The patent segments the synthesis into convergent modules where intermediates are prepared separately and then coupled. The cyclopropyl intermediate and pyrimidine intermediate are synthesized through parallel routes and then joined in a final coupling step. This convergent architecture reduces the longest linear sequence from 14 stages to 7 stages, as each module can be optimized independently and scaled separately before final assembly, making the route suitable for commercial production.
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 new route achieves a more efficient, cost-effective, and environmentally sustainable production of the compound by shortening the synthesis to 8 stages with a 7-stage linear sequence, improving yield and reducing resource consumption.
Implementation Method 1
asymmetric sulphur oxidation of a compound of Formula (III) by reacting with an oxidative enzyme
Implementation Method 2
by reacting with an oxidative enzyme (Scheme 2)
Implementation Method 3
photo-catalyzed reactions
Data Source
AI summary
The present disclosure concerns the large-scale manufacture of pharmaceutical compounds, and novel intermediates for use in the manufacture. International Patent Application WO2011154737 discloses morpholine pyrimidines useful for treating cancer, processes for their preparation and pharmaceutical compositions thereof. In particular, WO2011154737 discloses, as experimental Example 2.02 on page 60, the compound 4-{4-[(3R)-3-methylmorpholin-4-yl]-6-[1-((R)—S-methylsulfonimidoyl)cyclopropyl]pyrimidin-2-yl}-1H-pyrrolo[2,3-b]pyridine (hereafter referred to as the compound of Formula (I)). The structure of the compound of Formula (I) is shown below. A synthetic route to the compound of Formula (I) is described at pages 51 to 57, 66 and 67 of WO2011154737, and is summarised below in Scheme 1.