Chemistry 236

Multi-step Synthesis

Spring 2008

 


S. Murphree (smurphre@allegheny.edu)
C.215 Doane Hall of Chemistry
332-5358

Office Hours: MTuThF 11 am - noon, W 1 - 2 pm, Th 8:30 - 9:30 pm and by appt

 

 

 



Assignments

The Honor Code is in effect for all activities, assignments, and reports.

 

 

 

General Philosophy

This laboratory experience is designed to develop skills for those students who will need to carry out synthetic organic chemistry in an independent setting at some later time. It is required for organic comp students, and is also appropriate for any other comp students anticipating synthetic work and/or students who will be applying for graduate school or industrial positions involving laboratory synthesis.

The structure of the course is designed to foster independence, so there is a minimum of “cookbook” chemistry. You will not be spoon-fed information, and you will often be required to make critical assessment of results which have no “right answer”. In short, the aim is to equip you with the tools necessary to be successful in a laboratory-based profession.
 

Specific Goals

An adept experimentalist is often described as having good hands. This is an allusion to meticulous technique and attention to detail necessary for any reproducible result in the laboratory. However, this is only part of the story—a good chemist must not only be able to execute a complex procedure, but he/she must also have the knowledge to design a reasonable experiment and to interpret the results obtained. This course has several specific goals aimed at developing these abilities:

Advanced techniques
  • TLC analysis of an unknown
  • Flash column chromatography
  • Recrystallization
  • Manipulation of water-sensitive reagents
Reduction to
practice
  • Interpreting advanced procedures for lab experiments
  • Planning and executing multi-step syntheses
  • Using primary literature to find appropriate experimental conditions
  • Following the course of a reaction/determining end-points
The post mortem
  • Preparation of an analytical sample
  • Interpretation of spectral data
  • Determination of identity and purity
  • Construction of appropriate reports

Reports

Four reports are due throughout the semester, each one with a slightly different format. Detailed guidelines regarding format can be found in the lab manual, and these guidelines must be followed explicitly. All pertinent spectra must be properly labeled and attached to the report. All purified compounds must also be submitted at the end of the lab, so make sure you keep track of them! Lab reports will be graded on content, format, documentation (e.g., spectra, etc.), as well as the yield and purity of the compounds, where appropriate. Reports are due on the dates indicated-late work will result in grade reduction.
 

Experimental Plan

Before you begin each module, you must submit a detailed experimental plan. This plan includes specific goals and activities for each lab session and a list of special equipment needed. You will be graded not only on the quality of this document, but also on how well you track it over the course of the lab. In other words, it must comprehensive and realistic.
 

Preparation &
Technique

The success of any experiment depends upon technique, and every aspect of lab work has a technical component, including the preparation of glassware, assembly of apparatus, weighing & charging reagents, work-up, purification, labeling, and documentation. You must learn to be absolutely uncompromising about technical expertise, so attention to pre-lab tips is vital. Just plain sloppiness will impact both technique and safety (see below).

Notebook

The laboratory notebook is an indispensable tool for the organic chemist and it is therefore a central element of this lab. Detailed instructions for keeping a lab notebook are in the lab manual-you are responsible for this information. A duplicating notebook is required for this course. You must turn in copies of your notebook pages before leaving lab each day-no exceptions. Failure to turn in your copies will result in a notebook grade of zero for the day.

Safety

This category includes: a) your safety, b) the safety of your labmates, and c) the working order of the equipment. You will be held responsible for the proper use of personal protective equipment, for example, safety glasses, gloves, splash and blast shields, etc, and generally minimizing your exposure to any laboratory chemicals. In addition, you must maintain a safe working environment in the lab. This includes things such as labeling your samples, keeping your lab drawers pushed in (this is a trip hazard), behaving responsibly, and the proper storage, labeling, & disposal of waste (waste should be minimized as much as possible). Never operate equipment in such a way that might result in personal injury or in damage to the apparatus. Don’t take safety for granted!

Withdrawal

The last day to withdraw from the course without penalty is Tuesday, 19 February. After that deadline, dropping the class will result in a failing grade. Please take this to heart.
 

Grading

The final grade will be computed on the following basis (no curves!):
10%                n-BuLi report (incl. notebook)
10%                Report on unknown (incl. notebook)
10%                Experimental plans (Modules I & II)
20%                Full report on Module I (incl. notebook)
20%                Full report on Module II (incl. notebook)
10%                Preparation
10%                Technique
10%                Safety

A

A-

B+

B

B-

C+

C

C-

D+

D

F

 

100-93

92-90

89-87

86-83

82-80

79-77

76-73

72-70

69-67

66-60

< 60