Naphthyridine Synthesis Scale-Up via Segmentation
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Solution Overview
Problem
The synthesis of substituted 1,8-naphthyridine compounds on a larger scale, such as kilogram quantities, is challenging due to existing methodologies, which limits their production and application.
Innovation Solution
A new scale-up methodology involving specific chemical reactions, including treatment with thionyl chloride, non-nucleophilic bases, aminoacrylates, alkylamines, reduction steps, and acid activating agents, is developed to efficiently produce compounds of formula (1) in high yields and safety, enabling large-scale production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If existing synthesis methodologies are used, then the compounds can be prepared on laboratory scale (mg scale), but the production cannot be scaled up to kilogram quantities
Solution Approach 1:
The synthesis is divided into distinct modular stages: (i) formation of compound of formula (2a) using thionyl chloride, (ii) reaction with aminoacrylate and base to form compound of formula (2b), (iii) cyclization with alkylamine to form compound of formula (3), (iv) reduction to form compound of formula (4), (v) reductive amination with 2-indanone to form compound of formula (5), and (vi) hydrolysis to form compound of formula (6). Each stage is optimized independently for scale-up, allowing laboratory procedures to be systematically translated to kilogram production while maintaining control over reaction parameters and intermediate handling.
Solution Approach 2:
The methodology optimizes critical reaction parameters for scale-up including stoichiometric ratios of reagents, temperature profiles during each reaction stage, solvent selection and volumes, reaction times, and purification conditions. By systematically adjusting and controlling these parameters across the multi-step synthesis, the process transitions from milligram-scale laboratory conditions to kilogram-scale production while maintaining high yields and product quality.
2Productivity
If existing synthesis methodologies are used, then the compounds can be prepared with acceptable yields on small scale, but the yields and efficiency decrease when scaling up
Solution Approach 1:
The synthesis methodology enables continuous processing through optimized reaction sequences where intermediates are carried forward without extensive isolation and purification between steps. Compound of formula (2a) is directly converted to (2b), then to (3), (4), (5), and finally (6) in a streamlined sequence. This continuous action minimizes batch processing interruptions, reduces cumulative losses during transfers and purifications, and maintains high overall yields even when scaling to kilogram quantities, thereby improving productivity.
Solution Approach 2:
The methodology performs preliminary optimization of each reaction step under laboratory conditions before scale-up, establishing optimal reagent ratios, temperatures, and times that are then maintained during kilogram-scale production. This preliminary characterization of reaction kinetics and equilibrium conditions allows the process to be executed efficiently at scale without the yields and efficiency deteriorating, as the fundamental reaction parameters are already optimized for maximum productivity.
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
This methodology allows for the efficient and safe production of 1,8-naphthyridines on a kilogram scale with high yields, overcoming previous challenges and enabling their broader application.
Implementation Method 1
treating a compound of formula (2) with a chlorinating agent which is thionyl chloride under conditions sufficient to obtain a compound of formula (2a)
Implementation Method 2
treating the compound of formula (2a) from step a) with a non-nucleophilic base and lower alkyl N,N-lower dialkyl aminoacrylate to obtain a compound of formula (2b)
Implementation Method 3
reducing the nitro group of the compound of formula (3) from step (a") to obtain a compound of formula (4)
Implementation Method 4
treating the compound of formula (4) from step (b) with 2-indanone and a suitable reducing agent under conditions sufficient to obtain a compound of formula (5)
Implementation Method 5
hydrolysing the compound of formula (5) from step (c) to obtain a compound of formula (6)
Implementation Method 6
reacting (6) with an acid activating agent and QH, under conditions sufficient to obtain a compound of formula (1)
Data Source
AI summary
The present invention provides methods of synthesizing compounds of formula (1) and intermediates thereto. The present invention also provides intermediates useful in the synthesis of compounds of formula (1).