In Melting Points We Trust: A Review on the Misguiding Characterization of Multicomponent Reactions Adducts and Intermediates

We discuss herein the problems associated with using melting points to characterize multicomponent reactions’ (MCRs) products and intermediates. Although surprising, it is not rare to find articles in which these MCRs final adducts (or their intermediates) are characterized solely by comparing melting points with those available from other reports. A brief survey among specialized articles highlights serious and obvious problems with this practice since, for instance, cases are found in which as many as 25 quite contrasting melting points have been attributed to the very same MCR adduct. Indeed, it seems logical to assume that the inherent non-confirmatory nature of melting points could be vastly misleading as a protocol for structural confirmation, but still many publications (also in the Q1 and Q2 quartiles) insist on using it. This procedure contradicts best practices in organic synthesis, and articles fraught with limitations and misleading conclusions have been published in the MCRs field. The drawbacks inherent to this practice are indeed serious and have misguided MCRs advances. We therefore suggest some precautions aimed at avoiding future confusions.

[Examination of warm and cold ischemic injury of small intestine by differential scanning calorimetry]

INTRODUCTION/AIM

Small bowel is extremely sensitive to ischemia/reperfusion injury. Therefore, we compared the effect of warm and cold ischemia on the intestinal structural changes by differential scanning calorimetry (DSC) method.

MATERIALS AND METHODS

Warm and cold ischemia groups were established on Wistar rats with 1, 3 and 6 h ischemic times (n = 30). Intestinal biopsies were collected after laparotomy and at the end of the ischemia periods. DSC measurement was performed on the mucosa, muscular layer and total intestinal wall.

RESULTS

Our DSC data confirmed that longer warm ischemia period caused more severe damage in the structure of the mucosa and muscular layers. The results of transition temperature and calorimetric enthalpy suggest that these changes can be reduced using cold ischemic procedure in University of Wisconsin solution. However, the extent of thermal destruction of each layers following cold preservation injury was significantly different compared to normal bowel structure.

CONCLUSION

In this study we quantitatively measured structural changes in the gut following ischemia using DSC. This thermodynamic method may provide basis for further investigations in different bowel stress models.