THE INTRODUCTORY COURSE IN ORGANIC CHEMISTRY: MINIMUM ESSENTIALS OF SUBJECT-MATTER* The character of the material presented in an introductory course in organic chemistry will depend somewhat on whether it is a one- or a twosemester course. It is my personal conviction that all students beginning organic chemistry should first have a one-semester survey of the subject, emphasizing particularly the basic principles of organic chemistry. If the student stops then he has had a brief, but broad view of the whole field, while if he goes on for another semester or more, he has a framework into which he can fit the more thorough and detailed knowledge that he must then acquire. The objection to starting the beginning student in a two-semester course and proceeding slowly and thoroughly to cover in a rather comprehensive manner the whole field of general organic chemistry, is that before the year is up he gets the impression that organic chemistry is a mass of facts, because he forgets much of the first part of the course before he completes the last part. But, if he has had a picture of organic chemistry, he will have some idea what to expect in the more thorough or specialized courses that follow, and they will be easier for him. Most of the students who come to us as graduates (the majority from small colleges) are so woefully ignorant of organic chemistry that it is necessary to give them another introductory course. Consequently, the whole field of organic chemistry is covered from the beginning, and developed rapidly and thoroughly, until a t the end the students either have had recalled to them all of the essentials of organic chemistry which they had previously studied, or have had the opportunity to learn them for the first time. Throughout this course every effort is made to get the student's knowledge arranged and correlated into a well-understood and usable form. The general topics in a one-semester elementary organic chemistry course are practically the same regardless of the college or university where the course is given. The important factor is the relative emphasis on each topic. There is ordinarily a tendency to include too much material rather than too little. The student will learn and remember more if what is presented is sufficiently limited so that he is not completely overwhelmed by it. In the elementary course there is always the question as to what subjects or details are of such importance that they must be included, and what should be omitted to make room for something else. A few of the more important points follow.
* Paper delivered at the joint session of the Divisions of Organic Chemistry and Chemical Education of the A. C. S. at Richmond, Va., April 14, 1927.
Presentation of Organic Chemistry.- In my opinion the division of organic chemistry into aliphatic and aromatic compounds for preseutation to the elementary student is by far the most satisfactory procedure from a pedagogical standpoint. In a second semester course i t makes no difference, in fact i t might usually be advisable to present the aliphatic and aromatic compounds simultaneously. Relationship to Inorzanic Chemistry.-The relationship of organic chemistry to inorganic chemistry, and particularly the characteristic differences, should first be pointed out to the student. Among other things this wiU involve a carefnl explanation of isomerism and experience in the writing of isomers. The nomenclature of organic compounds is either sadly neglected by the average teacher in the introductory course in organic chemistry or else the student has not been impressed with the subject sufficiently so that he retains even the most elementary facts concerning it. A couple of lectures devoted to a careful study of nomenclature is not time wasted, as the student will never thereafter be awed by a long organic chemical name. Nomenclature is as important for those who are merely taking organic chemistry in connection with some other field of work as for the chemist. The interest of the student in this field is easily aroused, and the explanation of two or three systems of naming the simpler organic compounds furnishes a good opportunity to point out how the science has developed and is still progressing. Functional Groups and Homologous Series.-Early in the course i t is desirable to emphasize the meaning and importance of the functional group and its significance as far as the reactivity of various compounds is concerned. The similarities and dissimilarities between these functional groups can then be considered as each homologous series is discussed. Reactions.- A common fault in an elementary course is the presentation of too many reactions to the student. One or two, or in special cases a few more, for each functional group are sufficient to illustrate how the compounds behave. The difference between general and specific reactions should be emphasized. A correlation of the mechanism of the reactions of similar functional groups always aids the student in remembering. OfiticalIsomerism and Tautomerism.- Optical isomerism is so important that it should always be discussed in an introductory course though it is better, in my opinion, to introduce it later than is generally done in the average text. It is inadvisable, unless a picked group is being taught, to attempt a discussion of geometric isomerism and tautomerism. These fields can better be considered in a second course. Compounds with More Than One Functional Group.- A minimum amount of time should be devoted to a discussion of those compounds containing
more than one functional group. There are a few complicated compounds important because of their very general natural occurrence, and there are a certain number of simpler substances such as glycerol, oxalic acid, etc., which can be used to illustrate the large number of products of reaction that are possible. It may even be advisable to point out, with one or two examples, the fact that two functional groups in a certain relationship to each other within the molecule will sometimes make possible certain special reactions. Natural Products.- The importance of natural products as sources of organic compounds should be emphasized, and sufficient stress should be laid on important facts concerning animal and vegetable oils, carbohydrates, proteins, etc. Practical Afifi1ications.- The average introductory student will have his or her interest in organic chemistry stimulated far more deeply if, wherever possible, the teacher takes the opportunity to point out the practical application of whatever compound may be in process of discussion. The fundamentals are appreciated much more if a clear understanding of the relationship of organic chemistry to everyday substances is pointed out. Electronic Concefitiom- The electronic conception of valence should best be reserved for discussion in the second course in organic chemistry. Students with a general knowledge of the field of organic chemistry are in a better position to give the proper weight to such conceptions than if such conceptions must be absorbed a t the same time as the more important fundamental facts are being presented.
